Camper kitchen doors

Hi everyone, i'm in the process of making a new kitchen for my camper out of plywood, liquid nails and screws.
My problem is i've put a door on and the wood is a bit bent and makes the top stick out and not close properly. I have tried clamping two pieces of timber either side for a few days to try to make it flatten out but hasnt worked.

I am no carpenter as you could tell if you saw the job ive done (gaps here and there lol) but it will do the job. Give me a welder and steel any day.

Any help would be aprieciated

Cheers Luke