I've been dealing with these people for the last f...

I've been dealing with these people for the last few months. They're nice when I talk to them, but they don't seem like they know what they're talking about. I keep receiving letters that I owe money, but I definitely don't. It takes sooo long to actually talk to someone about this. I eventually started emailing, but there hasn't been a response. It's been almost a month. So frustrating!!!