BAD Service and not adhering to turn around time on responses

I have been trying to get a hold of MTN trying to settle an outstanding account with them however there is no response from them. I've asked to be contacted as this matter has been on going and i keep getting automated responses requesting my security checks to be done, this account is from 2017 i am not sure of the details MTN has. Their customer service is so inefficient, i have tried contacting the call center however you have to be an MTN subscriber to get through. The service is horrible and i am trying to do the right thing in paying off my outstanding debt, i have contacted the debt collection company who was apparently dealing with this account and they have advised that MTN has withdrawn from their services. Please advise me on how i am supposed to pay off this account if there is no assistance from MTN and you guys do not even respond to emails? there is an 8 hour turn around time on emails yet i have not received a response as yet, only a response for verification which i have done 3 times already. This is rather appalling service and i do hope that i get contacted soon for assistance. I really don't even believe i should be giving MTN a rating we need a negative star rating for the service received!