Have you tried lubricating it with WD-40? If that doesn't work, you can invoke the warranty.

WD40 will lub the lock but over time it will cause a gum up in the lock. Use graphite that is specifically for locks.
Take the lock back to where it was purchased and have it replaced under warranty, they can rekey the new lock to match the present key. You can also call the manufacturer and they can troubleshoot and may replace for you if required.

Hi, If the key turns but the latch dosn't move I think the mechanical connection came loose. There is a piece of metal that goes from the key side of the lock through the latch and into the thumb handle on the inside side of the door. There is only one mechanical connection and that is on the key side, the rest of the metal slide into the rest of the parts. Gently take the lock off the door and look for the clip that came loose and put it back on.
Good Luck Woodbtcher

if one can take out the lock, fine. but what if you are locked outside the door? how to take the deadbolt out in such a situation without access to the screws that hold the deabolt in place from the inside??
thanks to all.

If you're locked outide the door then you shouldn't have access to the lock, otherwise it would be useless a security device. If you're stranded and can't get inside, I'd say it's time to call a locksmith.

If you get inside and can manually unlock the door and open it, then you should be able to remove the lock.

I caught my brother-in-law messing with the front door dead bolt. Now
The original key wont work.