demanding money for an account that was settled

I had a contract that expired in 2013.In 2014 I recieved a message that demand a payment which was supposedly the last payment. surprisingly because they used to debit my account. I decided to pay that amount,thinking they will stop bothering. I took the proof of payment to telkom where they scanned and sent to the accounts department. Unfortunately I still receive messages and phone calls with threats that I will be taken to court for not paying. Im really tired of all the phone calls and sms.<br> what annoyed me is that they took money from my account without my consent.I definitely reveresd it because I know that I paid them.Now they are concentrating on that,that I reversed the money I must pay.<br> <br> please help