How do I get a jammed door open on my Diplomat Dishwasher model no. ADP 813?

I have a Diplomat Dishwasher model no. ADP 8132. It is about 6 years old, used probably every other day.

The problem I have is that the dishwasher was put on to do the cycle (as usual). It went through the cycle and them bleeped to indicate it had finished. When I tried to open the door, it was stuck and we have tried every day for 2-3 days to get the door open (a pull down door). It is stuck completely. There is a little bit of movement at the top but it is jammed and I just can't get it open. It is an integrated dishwasher. I've had an electrical man to look at it, but he said he doesn't want to be responsible for damaging the kitchen. He said he has NEVER come across anything like this before.

Has anyone got any suggestions?