KitchenAid Double Drawer Dishwasher KUDD01DP

I do not use my bottom drawer very often so 1x a month I run a rinse to keep it clean. When I turned it on the drawer locked and started, but there was a thumping sound. I stopped it and opened it and tried to re-position the spray arm etc and started again - same thumping and then it turned off. There were no error codes lit it just stopped and beeped. A small amount of water was in the bottom. After about 6 tries I took it all apart and cleaned the parts according to the cleaning instructions, dried out all the water, unplugged, turned off the water source and after 10 minutes plugged it back in and turned back on the water - same problem. I have spent thousands of dollars on my KitchenAid microwave/oven combo - and I'm not exaggerating, I have used 3 different service centers from KitchenAid's site and it takes a minimum of 3 visits and hundreds of dollars to fix the problem. I have been without a microwave since May 14th - and $762 later we are suing that company and trying to re-coup our money from KitchenAid. Anyway the top drawer works fine, I just hate to try my luck with a new service center. I appreciate any advice you can give me. Thank you for taking the time to read this. Mandy