Bad service delivery

I have been chasing MTN after my SIM card was wrongly blocked coz of no payment. Only to discover that my Cell number was linked to a SIM card number that was already linked to another cell number. This has been going on since February. Till date no response or update. My number is still incorrect from what it is on the statement and what I’m using. When I reported I was instructed to go to any mtn store n get a new SIM card and discard the one mtn delivered to me. Mtn will then refund me for buying another SIM card as it was mtn fault and not mine. It’s not a September and I still send emails almost every second or third week with no response or feedback.