Unauthorized debited

I cancelled my contact with telkom in March this year( mobile wifi pocket route). However every since then telkom is still taking monies out of my bank account because its less then R200 the bank advised i can reverse it on my app on my phone which i have been doing, however over the last 4 months twice they have taken between R500 and R600 because of this large amount i need to go to the bank and of top of that pay a reverse fee, went back to telkom store i was advised ita been cancelled. However they cant answer why telkom is still taking out money. Absolutely disgusted with the level of service to run after my money on a monthly basis.