Poor service received from MTN

I have had a very bad experience with MTN, I don't even know why they keep calling me to offer new products. Took out a contract with them in 2017 around April (P-9lite phone), i was very specific that I want a 2 sim phone as I already had 2sim phone i wanted to give away. I was then given P-9lite phone, only to find that the other slot does not work. there was holidays in between which prevented me from returning the phone. i managed to return the phone the next available business day that's when i was told MTN phones don't take 2sims. I gave the branch the device with everything including the simcard, however they continued to debit me for 5 months even tho i gave the device back. Been driving back and forth to westgate branch wasting my fuel to follow up on the termination, i was shocked when I received an email from legal threatening me with legal actions to pay them when the contract eventually got cancelled. The agent that assisted me admitted to making a mistake when he sold the contract and agreed to pay the stipulated amount to legal so that MTN can credit me back. Its been almost a year now going back and forth trying to get my money back and when he finally settled the full amount they are refusing to give my money.

I would like MTN to give my money back with interest plus fuel that i wasted driving to the branch only to be told they are still working on it.