Billed for a service I didn't sign up for

On the 9 March 2023 I questioned my bill because it was sitting on nearly R6000, so the consultant send me a invoice for all my number and how they came to the amount. To my surprise I found I was being billed for god know how long some called "BF promo". Which I didn't sign up for. On 9 March they gave me a ref 8514b4a4-0a47-4d84-b3e1-903a6b2a0412 this was from the complaints department, on the 20 the department only responded to my query asking fir my ID number. On the 24 Mar I phone Mtn again in regards to the matter and was given yet another two ref *** and ***, the consultant said that her manager would call me back on that day to resolve the matter but till today not a single call. Mtn needs to tell Mr from when was the service added to my account and the money I paid monthly needs to be refunds. I would need hard evidence in regards to because they do not email me monthly a statement, I not aware for how many months I was billed like this. Being a loyal customer this is the service we get.