Bad service

This is now going on for to long. I went to the Telkom shop at Greenacers port elizabeth. I asked the guy to cancel my account as there was only 1 month left of the contract. He said its all done and it will be canceled so i left and never thought much about it. Now i keep getting calls that i have been given over and with this said they only phoned me about 6 or so months after i canceled the contract. Also the guy who helped me at the store said i dont need any paper work because i did ask him if i need anything. He stated no mam everything is done and you can go now. So unfortunately i dont have any paper work. But im sick and tired of getting calls the whole time after i canceled it and it's affecting my credit score.