Contact cancelled months ago however i am still getting billed.

for a couple of months i have been reversing debit orders until i contacted the CCC and asked why am i still being debited. the car was sold in march with the tracking device so when i asked why not debit whoever that has the vehicle now as they requested the service not me. till today i am being debited for what it is unclear - Account Number : ********** Contract Number : ********** 901 Cancellation Date : 28/03/2017 i even have a letter that shows that the contract was cancelled - but my account is still debited. spoke to Nokuthula a few minutes ago and she advised that she will investigate and revert back to me. note this is the second time calling about the same incident - and hope this time i wont make the 3rd call next month.