ITC harassment

ITC has been nothing but an harassment for over a month now, they keep calling me and sending me emails saying I owe money on an account which I do not owe money, I’ve sent through emails numerous times with proof that I am not in debt with that account, yet I am still being called by ITC staff. I’m beginning to think that they don’t actually look at the emails that get sent to them. Actually starting to feel harassed. The amount of times I get calls from these people weekly is pathetic and their staff have no manners. And all seem to have the “oh well” type of attitude.