It sounds like their furniture arrives in pieces and is put together onsite, either by them or by you.

Is the length of the sofa shorter than the height of your doorway? Because sometimes you can get a too-wide piece through by putting it on end and swiveling it through the doorway. However, it must be shorter than the doorway. I've linked an article that may be helpful to you. Ceiling height and stairway width are other factors that will affect you that aren't talked about in the article.

Here is a link that might be useful: Guide

The feet are attached to the base-
This is true----
But...
the back is not attached to the base..

Did you watch the "how to assemble video" ???

A 7 yo girl can do it in a minute.
Took the 8yo boy 5 min.
Perhaps he should have read the directions first :)

I have a 29" stairway to my second floor in my 100 year old house. I just ordered a Simplicity Sofa after doing a lot of research. They even put me in contact with a person in my area who had one, and I went to see it. Excellent customer service!

I got the "white glove" delivery that brings it inside and upstairs, sets it up, and takes away all the packaging. My understanding is that it some in one large piece with a folding down back, and two arms. There is a video on the Simplicity site that shows a child putting one together. The sofa I viewed here in my area was very, very nice--doesn't look or feel at all like furniture that comes in several pieces.

I'm just thankful for such a business. Furniture is made so huge these days and little to nothing is available for 100 year old homes with tiny spaces.