Cell c poor services

I am very unhappy with Cell c again I shorted out my account with them long time ago I paid them the money that they requested and everything was fine now today I get a email saying that they handed me over to hammond pole attorneys owing them an amount of R 60.70 for something that I did not use. I'm really not happy with Cell c and their services because when you think you shorted them out and everything is fine than they come back and hand you over to attorneys for something you don't even know about they don't even inform you or call they just decide to hand you over without letter there customers know what the problem is an how they are owing cell c services is horrible and I'm very unhappy once again because it's not the first time they do something like this