Debited for a service plan I canceled

I requested for a service plan on my vehicle to be canceled on the 22/08/2019 and I had taken it a few days before. On the 26/08/2019 I was debited my normal car installment plus the R112 for the service plan. I lodged a complaint and requested for the R112 to be transferred back and I was told my query will be attended to. Today I am checking my Nedbank online account and I am shocked to see that even for the next installment date the amount that is going to be debited still includes that R112. I keep calling them and speaking to different people who assure me my complaint will be attended to. It is absolutely disheartening and I wish I could cancel the vehicle finance altogether and finance with another institution. Mfc is very unhelpful and do not care about the customers.