HR screwed up my 401k. Won’t respond. Options?

im over 50 and eligible for catch up contributions to max out. I have documented proof that I elected a certain number of $ each paycheck be contributed to the ROTH 401k option. They started early in the year, and it was evident in paystubs. I just realized that after a short time, they started to direct my $ to Traditional 401k plus, a few weeks ago, they stopped taking contributions— at the younger person’s max. I’ve emailed via out ticket system, and have been told they are looking into it— and they arranged for this week ( yesterday) pay to have the ROTH max contributions reinstated. My check shows nothing taken out. After repeated no- replies, I had to cc a manager, explaining that I’m running out of time and my messages continue to go with no response. They screwed up with about $27k of my money. im leaving Dec 27th. Questions: Can my ROTH vs trad 401k issue be fixed? Can they take retro contributions since hey are doing nothing now?