Bad service

So disappointed with MTN, got a call that l owed mtn R94 000 for a contract phone that was taken in 2018,which l didn't apply for, someone used ********** documents. Only to be contacted in March 2021 that l must pay. Went to mtn store was adviced to go to the police station and get an affidavit and a certified copy of my ld, which l did, they told me that they will investigate and it takes up to 6 weeks. Went back after 6 weeks was told that the investigation is still open l should come back after 2 weeks, which l did got the same story, have been phoning and going to the store same story still investigating, l am really running out of patience now and my credit store is affected, l feel like nothing is being done, the manager of the store l went to escalated the matter but stil no way forward, its been 12 weeks now no feed back