MTN cant even send an Invoice

Something as simple as sending an invoice and MTN can not do it. I have been trying to get this resolved for a few months now. I have so many reference numbers it is just not funny. All of them closed within 24 hours and the issue is still ongoing. Correct me if I am wrong but the customer protection act states you must provide me with an Invoice. There is no accountability as the agent tells me every time they are sending the issue to another department and they can not be contacted. if you enquire they say the request has been closed. nothing is done. MTN does not deserve my business anymore.