Cell c contract cancellation . No response from 084 145

i had a data contract for 2 year period. After the 2 years I could not stop the monthly deductions at a cellc shop. They said I must cancel the contract phoning 084 145 and select option 2 which I did. They simply put you on hold and wasting time and money. After an hour I have achieved nothing but wasting money on cellphone calls. I don't know what to do to cancel a contract after its expiry date have been reached and they continue deducting moneys. All I could do was to cancel the debit order and most possibly now they will keep on billing me for nothing