Poor verification service

Mtn does not really verify their clients necessary required documentation before they can engane on a business. I have been a victim of identity theft and I reported that. two accounts were opened in Mtn not sure where exactly but the person managed to open the account/contract. Due to Mtn not doing their proper job I have been blacklisted for something or goods I've never received. I want to sue the company for ruining my credit score. Please help which channels to use ********** 639