Bad service at MTN Tyger Valley

During March this year I renewed my contract to one for R199.00 which was for 10G data during the day and 10G at night. Since the first payment was deducted from my account it was more than double this amount. Despite the fact that I have complained with the manager at Tyger Valley the problem has not been resolved. I then cancelled my debit order. Despite this they deducted the wrong amount from my account again today. They are already not willing to refund me before 13 July 2018 for all the wrong amounts deducted. This is now my third contract with MTN and the service is really pathetic.