MTN gives BAD service

I am disgusted in the service provided by MTN I've been trying to pay up/ sort out a deceased persons account for the past 5 months now. they keep telling me to call 135, when I do they tell me to send a mail with the document, which I do and then they tell me to call 135 again, and when I do I get told to send the mail again. is it so damn difficult to just tell me what the settlement amount is so i can pay it and transfer the number to prepaid