MTN will not refund incorreclty billed contract

I previously put a complaint on Hello Peter and received a response from MTN. I then sent the below response back to them. As yet I have not received feedback. So I will create a new complaint and hope for a reply.

I was incorrectly billed from 25/4/2018 to 25/7/2018: 25/4/2018 R937.75 25/5/2018 R937.75 25/6/2018 R937.75 25/7/2018 R937.75 This means that an additional R 462.62 was taken off my account four times, so I am owed R 1850.48. I was supposed to be billed R 475.13 ( please check your records as this is what I am currently being billed. Please get back to me as soon as possible with the confirmation of the refund.