IF you give it back - and walk away with your deposit ... I'd like to see what happens in a couple days if you hold your mud and refuse to increase the sale price. I'll bet in days, that dealer will be back at your door with the same price.
Unless he sold it for more during the time the bank delayed, and now is getting out of the first one for a better offer. We talked ethics earlier, but sometimes folks that have received such treatment personally in the past are very, very difficult to convince something shifty might be in the works here.
Unfortunately, too much happens like this in RV and auto buying - no trust, and a lot of manipulation with contract, finance, trade-in value - almost impossible for anyone to feel totally comfortable with a deal even in the beginning, and now, this emerges -- Might be a real error, but I'd sure not take a bath on it ...