Bad Service

I've paid up the account, and requested a paid up letter. I haven't received anything, just continuously receiving phone calls stating that I still have an amount outstanding. Even received a sms stating my balance. Logged in to the account, and saw additional costs were added, after the account was settled, I've sent emails to *** and *** with proof of payment, requesting the paid up letter, and to close the account... No communication.... but they can call you to tell you that you still owe, after account was settled.