Unauthorised debit not being refunded

Once again no service from MTN. After MTN made an unauthorized debit on my account I put in a complaint at their call center as well as on Facebook. Spoke to Michelle on messenger and after she assured me that my issue will get resolved and now it once again just got left and nothing is being done. Very very poor and I expect MTN to sort this out now. It has been 10 days and nothing !!