MTN ******S

I took out a MTN contract via Mondo in 2020,I've never received the phone,nor signed for delivery.MTN has ever since blacklisted me,for something I don't have.2 yrs of phone calls between MTN & Mondo but no results.I don't know what to do anymore. I want to buy a house but it's counting against my application. Please I need assistance as I don't know what else I can do. Lawyers will cost me n everyone says I must just pay .Unfortunately I won't pay for something I've never had