TEXT MESSAGE ABOUT OUTSTANDING AMOUNT

On 27/7/15 i got an text message fro cell c - ( ***) stating that my account is overdue with R6 and I must pay it. So I called the called center and the agent look on the system and said that there are non such message send out to me and that it must be a system error, I asked for a reference nr 150727. Today (31/7/15) I receive another sms: Your account is 1 day overdue by an amount of R6. Please settle??? Why do I owe you money? I did cancel my contract and according to the agent it will only be canceled on 13/08/2015 and that another debit order will go of on the 1/08/2015 because I did not give 30 days notice, with is also absurd because my contract that I have signed for ended on 1/08/2015. I am not going to pay R6 in via EFT the banking fees are more for me to pay the stupid R6. So if I owe you R6 take it with the debit order that I need to pay anyway on the 1st of August but STOP Sending a text that I owe you money. This is just confirmation that I did make the correct decisions to cancel my contract.