Ladder removal

Hello everyone. I am new here and this is my first post. I want to remove my ladder so that I can put a new cover on my pool. I noticed that each rail has a bolt beside it in the concrete. I have learned that it is an anchor cup with a wedge in it. From what I have read and seen, you are supposed to loosen the bolt about 3/4" and then tap the bolt back down to loosen the wedge. I tried doing this, and the bolt never went back down. I even bent one of them trying to get it to go back down. The ladder has not been removed since I have lived here (7 years) and I am afraid that it might be corroded or something. Is there a way for me to break this wedge free so I can get the ladder out? I was wondering if I could stick a screwdriver down in the bolt hole and hammer it that way to break it free, but I don't want to damage anything. Any help would be greatly appreciated.

Thanks,
Kevin