Contract not cancelled after instructing consultant to do so

I am disgusted by MTN. I was cancelling my LTE device contract. I was given clear instructions to go to the store, hand over the device and SIM and cancel the contract.

I did precisely as I was told. I told the consultant at Festival Mall to cancel the contract, but she didn't. The Debit order went off, and I was told to return to the store to cancel the MTN.

This is unacceptable because I'm told I must return to the store.