Ben, I'm sorry you're having a problem with Proline.
I purchased a Proline hood a little over a year ago and have had no problems,
At the time they were great to deal with and they made a good product at a great price.
Certainly you've called them.
What have they said?

My experience has NOT been good, to say the least I am very frustrated.
Placed order for PLEW832.36 1600CFM with 10' chimney extension Jun 20, 2011. ProLine informed me the design was changed, instead of one motor at 1600CFM, the redesign was 2 motors with 1000CFM. I asked about the venting, my response was we have a gasket that covers both outlets to converge into one, ok so I have 1 hole in my wall for the vent, is that right? yes was the answer. Vent did not arrive until Aug20 2011. Vent did not come with the gasket they said it would, I called to inquire about this and they now said it needed its separate vents to beyond the wall and then could be joined into 1 pipe. Installed about 2 days later. As our kitchen did not have a vent, we had to have one installed, quite a process, as we have a room above the kitchen. Turned on the vent and such a racket... quietest on the market, don't think so! So I called Tech support and spoke with Spencer, he said it was not supposed to sound like that and they would send another one to replace the one installed. Also, the chimney extension did not arrive at the same time, called and they said it was on its way, it was delivered Aug 26 @ 6pm! The new vent was delivered Oct 27 2011. Called the installer to come back and take out the old and replace with the new. Guess what! Still the noise, not as bad, but still very noisy. I placed a call to ProLine for tech support and was told he was out of the office and a message would be given to Spencer for a callback, I am still waiting for that call. I was looking for a different type of "Y" connecter and a distribution center for HVAC advised me to call a company which specializes in vent work. I did, they took a look and said it needs 2 separate vent runs. However as they were preparing to do the work yesterday late afternoon, they removed the vent pipe and still the noise on one of the motors, sounds like the left. The installer said it sounded like the bearings were bad. I called and spoke with Heather, she said she could do nothing about it and will talk with Spencer on Monday. As a footnote, this company is a venting company, that is all they do, they install Viking, GE, Dacor, etc... high end vents, they have been in business for 40 years, so they should know what they are doing.
All of this has been a great expense, each time they have to come back it is more money. Now, the vent company, will add additional vent at a cost of about $350. So this install process has cost us as much as the vent ... Vent with chimney $1000, first install $630, additional install $350. Also, manual that comes with the vent is for a single motor. I feel that if they changed the design, venting is a big process to making the vent work properly, they should have advised on that process and have new manuals made.
I must say that Proline has been very accommodating, but they don't tell the truth about when the product will be here (too many conflicting excuses). I think 2 months wait each time is a little long for arrival. Perhaps they should put more vents on that slow boat from China!
Sometimes what seems to be less expensive turns out to be more expensive, than if you had chosen a more expensive one in the first place.
Please CHOOSE carefully.

I also had a TERRIBLE experience with ProLine. After extensive research trying to find a good balance between the look, functionality and price I stopped on ProLine PLFW 520.36 . The website stated that the item was on back order and was expected back in stock at the end of October. Before I ordered I called the customer support and got their reassurance that the item would indeed be in stock shortly. I placed my order on October 27, 2011.

To make the long story short -- The hood that I ordered NEVER ARRIVED.
In the middle of December I had to settle for a model that wasn't my original choice (I needed to finish the kitchen after all). I had to spend numerous hours on the phone trying to get in touch with somebody because NONE of my phone messages were ever returned.

Before agreeing to a different model I had a conversation with the customer support to make sure that the model I was going to settle for did indeed have dimmable lights as the website claimed (it was one of the key features for me). Again, I was reassured that the description on the website was accurate.
When the hood finally arrived the lights WERE NOT dimmable. Customer support reply - "We are sorry that it doesn't work".
After all ProLine does not create an impression of a serious business - the PayPal payment goes to a person and not a company, the same lady (Heather) handles sales, customer support and technical support calls and emails. When I asked for a receipt for the new order model vs original order they told me they "couldn't do that". There is no documentation to support the claim of "2 year limited warranty".

I WOULD NOT recommend ProLine to anybody.

I purchased a cylindrical island hood for an upcoming renovation. 3 weeks later I received a call that the unit had been damaged in shipping. I was understanding and ordered a somewhat similar hood. When we opened the box we realized that the charcoal filters had not been sent. As our hood does not vent outside of our loft these are obviously essential.
When I called, Proline apologized and said they would send the filters. They arrived a week later but were incorrect for my hood. Another call, another promise to send the correct filters. Again, these were incorrect.
All subsequent calls and emails have remained unanswered. They are actually ignoring me.
Since, I have registered a complaint with the Better Business Bureau in Utah to try and have this resolved and received an email back from them today:
The Better Business Bureau has made two attempts to contact the business regarding the above referenced complaint. We regret to inform you that we have not received a response from the company.

This complaint case has now been closed as an UNANSWERED complaint in their file.

The Better Business Bureau develops and maintains Reliability Reports on companies across the United States and Canada. This information is available to the public and is frequently used by potential customers. In the case of your complaint, the company's failure to promptly give attention to the matter will be reflected in the report we give to consumers about them.

I am now stuck with a nice looking but completely useless range hood that I can not find filters for.

Do yourself a favor and shop elsewhere!!