The house I'm living in was rented through byers a...

The house I'm living in was rented through byers and harvey initially, but switched at some point to platinum realty. I found out about the switch when I received a check in the mail from byers and harvey because I'd overpaid an extra $5 most of the months I'd been in the house. I paid my rent then and I haven't stopped, but for some unknown reason I get some piece of paper claiming I owe over 4x's the amount of my monthly rent! I've made several attempts to get in touch with the woman in charge of this but here i am writing this waiting for my attempts to be acknowledged. Who knows how much longer after that point before I can get some answers? !
I just really have a difficult time believing that any company would allow 4 months of nonpayment to pass before deciding to take action. This is blowing my mind, it really is