Elon Property Management

I left my place at *** on Aug 22, 2020, just like the lease said. But I tried to tell Elon Property Management many times and in many ways, like calling, leaving messages, and going to the office. But nobody was ever there and nobody ever called me back. I know things are different now because of the pandemic, but I still got charged a lot of extra money, which is crazy.

I emailed Elon Property Management on 7/21 'cause I couldn't pay rent on *** and didn't hear back before 6 pm. So, I went to the rental office to drop it off, but traffic on 270 made me late. When I got there, I saw that someone left both my windows wide open and my apartment unsecure. Some of my stuff is missing, and I can't replace it. The missing items are worth about $3,500. This was reckless and dangerous, and I'm frustrated 'cause it put me in danger. I want my stuff replaced or fixed asap.

I lived at this place for a while and decided to go month to month till I found a new spot. They told me it would cost $160 more each month and I said okay. I paid on time and left on January 21st, even though the contract ended on January 31st. I let them know 30 days before I left.
But now they're charging me $124 for "apartment rent market" and $498.19 for a month to month fee. I thought that fee was already included in the extra $160 I paid. I emailed them 4 times and left a voicemail, but they haven't gotten back to me. This will mess up my credit if I don't pay it, so I want to work it out, but they won't talk to me. Please help.
Thanks.