Telkom

Mondo telkom had become my worst nightmare, I took a 24 month contract with them, the deal contained 4 Sims and 1 phone Samsung galaxy grand , I have finished paying the contract but they are sending me some balance to pay again. I did called them about the issue and they told me that I'm supposed to cancel the contract,.i took a 24 month contract which is already paid off and now they are telling me to cancel the contract .what contract, mondo telkom is not a trustworthy company. They are biased ******