Bad Service from MTN Southgate

I app**** for a cellphone upgrade at the MTN Southgate branch (the one by checkers) on the 07 February 2018. I asked the consultant who was helping me (Simphiwe Nteyi) to add a 2 gig booster on my contract which he added as it shows that its there on the contract that I signed. However for the past two months they have not been adding the 2 gig booster on my contract (please note that I am not being charged for the booster but instead spend about R300 a month buying 2 gigs of data to supplement the 350mb I currently get). It has now been over a month and my query has not been resolved. I have been to the store three times and called Simphiwe several times to find out the progress. He keeps telling me that he has reported the matter and is following up. I keep being sent reference number after reference number. I was then asked to call 808 to follow up myself on those reference numbers, what do you even call that? How long do I have to wait before this is sorted out? Please can you assist me because clearly the staff at the Southgate branch cannot.