Overcharged

Please help me get my R29 back from Mtn. I have a contract with them and in July they changed me extra. I phone their call center to make an enquire and they told me I have a roaming activated on ny contract and it shows that I made a call out of the county. After logging a call with their call center i was told they will do an investigation, I did a follow up and was required to confirm where I was at that time. Which we were on lockdown as a country and my passport is long expired, so there is no way I could have been out of the country. I further escalated the matter to their Twitter page. But they always tell me they are waiting for feed back from investigating team. How long should it take? Every time I get given time frame, yet this case has been on from July. This is a 5th month. Maybe to them R29 is nothing and they feel I should not demand it, but where is honesty and integrity from MTN. After being with them for so many years and this is how they treat me? Look at Unathi's case, it was resolved in less than a week, yet it was thousands of rands, and just because I'm an ordinary customer, they give me a run around? *** Ticket loged 21st *** Another one 1-***3th aug *** *** These are all ref numbers i have been given.