Horrible service and service consultants

Paid off my account but now I'm receiving calls every 10 mins from their consultants saying I'm behind with my payment, I settled yet they still debited and couldn't receive my money now I asked can someone call me with a straight story cause each consultant keeps saying they will check my account and get back to me but never do instead someone different will call .I find it annoying that they can't even track what was said in the previous call ,I've gone as fat as switching off my phone because of the endless calls but no1 gives me the feedback I required.