TRS screwed up my mom's insurance - she is in remi...

TRS screwed up my mom's insurance - she is in remission from cancer, by the way, and has tons to pay for with recovery. I sat with her as she filled out the paperwork to switch insurance IN THEIR OFFICE when she retired in February for a September switch. Low and behold, when September came, we were no longer covered because they didn't submit the paperwork. Oh, and they took $53,000 from us to buy back out of state services and are now saying we didn't pay it.