Mtn Duplicated my number!

I've reached a point now where I don't ever want to deal with this network and my frustration grew over the past weeks. I initially had a contract taken on my brothers name with Mtn for a data deal (50gig for r150) and when this contracted ended I still wanted to keep my number so I've used it on prepaid until I saw a data deal with Mtn in April 2019. I on my own app**** for this contract and it was successful on my name only to find out Weeks later that this number that I'm currently using has been given to another customer in Johannesburg even though I've been using this number on prepaid all along. I've been going back and forth into the Mtn store (city view Durban) to try and rectify this problem but there has been no assistance from Mtn SA after the sales person that I've been dealing with sent through countless of emails. This is a big problem for me as this number im currently using has been with me for many years and iv ported to Mtn from telkom. I have spoken to Mtn call centre agent myself in retentions department (Ayanda) and she tried to help me but nothing has come through afterwards apart from emails stating that my problem has been resolved.. It even went to the ***** department and they gave feedback that there's no ***** as per Ayanda. Mtn will never be able to compensate me back for the amount of stress they put me under as well give me my number back so I can move over to another network. I've emailed Mtn *** and they take forever to respond and everytime they responded it was a different person. I always thought Mtn was the best network up until this point where I don't want to have any dealing with them I just want to move to another service provider. I had to bring this story to hellopeter so other users don't fall into the same situation like me. The sales person that I've been dealing with at store level ( Mtn city view Durban) Faieeza, ***. I can't even count the amount of emails that has been sent to MtnSA from her side and from me directly. Very very poor from Mtn. I would never recommend them to anyone, and all my family that are dealing with Mtn will now move over to another service provider. Please help.