Continuously pinging my bank card, terrible service from chegg.

The service was OK when I was using this the only thing is that once you forget and they charge you when you cancel it doesn't really cancel as you are in the new month period to use it. I haven't used it. Spoken to multiple Associates from chegg.com on their chat and they say they cannot cancel and it will continue pinging my bank card due to insufficient funds till they get their funds. Now every ping my bank has charged me R3 and there has been about 20 so far. My bank cannot reverse it as it is not a debit order but rather a recurring card purchase. My only and next step if this continues is to go cancel my card and get a new card and never use chegg.com ever again. Their support os totally useless and this is absolutely wrong. They should be able to cancel it indefinitely and check if you haven't used the subscription and refund if you have been charged.