Popping lids

I have canned about 30 pints of green beans and every lid has popped up and the green beans are spoiled. In my 30 years of canning, I have never run into this. I even boiled the last batch in a hot water bath for 30 minutes instead of the usual 20 to make sure that they sealed. What am I doing wrong?? They are all new Ball lids. I'm going to write to the company. Maybe they had a bad batch or something. Has anyone else had this problem?