MTN customer care non existent

I have spent most of the day trying to contact MTN regarding a billing problem on my employer's cell phone. Their system is designed to ensure you never speak to a person and most definitely not to a person that will resolve any problem you have. I have emailed both customer care and complaints and have not received a reply. I have contacted the Sandton store but have not been able to speak to the manager or get contact details of a person who can assist. They claim they can only assist if you go to the store which my employer cannot do. The head office landline is picked up by the automatic system and continues to ring for minutes on end. When trying to make international calls from a contract device, a message stating that there is insufficient airtime is received. Surely this should not be happening as the user is billed monthly for calls made. There must be a way for MTN to correct this without the inconvenience of having to visit a store. I would appreciate someone who can resolve this problem contacting me as soon as possible.