Bad Service

I have a contract with MTN which is due for upgrade in May 2018.In mid Dec 2017 I received an sms saying I have received free 10gig data I went to check my balance I saw that have minutes, smses, and 12gig data of which my current contract I am entitled to 2gig. I called the Call Centre they told me I have upgraded and it was successful I was very shocked because I did not apply for anything at MTN and I was waiting for May 2018, the lady who was assisting me said I must visit a nearest MTN store with Id copy and avidavit. I visited the branch in Nonesi Mall in Queenstown I dropped the documents I was told I will receive a call from the head office.2weeks passed not phone call ,on the 9th of January 2018 I went to Hemingways mall in EastLondon I was told there was nothing recorded on their computers I must submit the documents again they gonna lodge the complaint again I must wait for 21 days they gave me the reference number for the case:1- ********** 5904.after 3weeks I received an sms instructing me to pay R549 I phoned the call centre I was told the case was closed I asked them how come because I did not get any response from Head Office not a single call or email to inform me about the outcome of the case, then they said they are going to re-open the case again they gave me a new reference number:1- ********** 5484 and said I must wait for 3weeks. I kept on receiving these sms's informing me that they are going to suspend my account I called the call center I explained the situation and I told them I do not have that kinf of amount and the lady advised me to pay the normal instalment, I paid R300 in feb but I kept on receiving smses they blocked my phone twice which is the number I use to receive calls , I can even load airtime because if I dial a number it takes from the minutes not from the airtime bought. I cant even focus because this thing is stressing me.I have been a loyal customer at MTN for year not a single months I missed my payment but they are treating me like ****.What pains me more is not even receiving a call from Head office just to appologise and inform me about the progress they are pretending like everything is fine. Very bad customer service, this is affecting my credit profile. How can an investigation take more than a month , its going to 2month now with no feedback.MTN is a big company not a fly by night. I am very dissapointed and I am thinkinh of taking this matter to Ombutsman because its beyond my control.