Unexplained charges

I have paid up my account in 2015 due to me being retrenchment. Which means my balance was 0. Now in 2017 I'm receiving statements and SMS that my account is in arrears. Every time I phone too customer services receive reference numbers and then gets told it's resolved. I am still getting SMS that I owe monies for a magazine that I need too pay, I have not asked for the book, I have not received any books, why the hell am I getting charge for something that I did not ask for. Please sort your accounts department I'm am sick and tired of having too phone again and again for the same queries.