MTN INSP (Internet Non-Service Provider)

I complained to MTN about the steady decline of my ISP service during 2014, to the extent that it was greatly affecting my livelihood (I'm a Web Designer, working from home) on 19th January 2015 (via their website - MTN REQ:***.) and received their automatic pro-forma response soon after - since then NOTHING!<br> They promise, and I quote ...<br> Your complaint will be fully investigated and we will provide feedback within 5 working days<br> BULLDUST! - I have had no human communication from them at all. <br> Why do SA companies not provide the service they are paid for and to top that do not have the courage and decency to contact a complainant, personally?