what would you do?

If I were in that situation again I would ask for the refund.

I am already having the same situation with a similar camera and the same seller.
This is the first time I have anything from KEH with a problem, they already sent my camera back to me with absolutely no evidence of them fixing the issue even though they said they did repair it. Now the camera went back to KEH a second time and they said they sent it out to someone else for repair.

To be honest I did ask for the repair instead of refund but it seems to be more trouble than it is worth.