MTN stole my money

MTN sent me an sms that a debit order of double my monthly contract price was going to go off on he 2nd of January. I immediately went to MTN in Worcester and inquired about this amount. They said that it happened to a few of their customers and that it’s a problem on their system. They told me that only my monthly amount of R819 will go off and not the doubled amount of R1649! This morning I got a sms notifying me that a debit order of R1649 went off! This is unacceptable. I went to Paarl mall MTN this morning to rectify this amount and it happened to the customer in front of me as well. They told me I must go to the bank and reverse the debit order. This is costing me time and money. I pay a lot for this service. I expect it to be correct. This is absolutely ridiculous!