Cancel my service already!

This account was suppose to be cancelled by there's still an account following me around as if we did not pay for it. The following was received on the 21st Feb 2020. Meaning that the cancellation of this account was confirmed and received. I then get calls from lawyers threatening me to pay because unpaid account that Telkom was suppose to cancel months ago.

We already paid whatever outstanding balance during the cancellation process.

Your case number: ***2 Service number to be cancelled: ***

I want this account removed immediately, the account rectified and my credit record cleared.