MTN refuses to RESPOND!!!

I am honestly extremely angry and frustrated. I moved to the U.S. about a year ago to pursue a Master's degree, with the intention of coming back to SA once I am done in 2 years. I therefore cancelled my MTN contract and put myself on prepaid airtime as well as sms roaming. I usually put my MTN sim into my phone when I need to log into my SA bank accounts etc as they send me a OTP. MTN disconnected my number without contacting me (no e-mail etc was sent to me). I e-mailed them regarding this requesting assistance. I have posted on FB, Twitter etc. and 2 months down the line I still have not received feedback or assistance. I am extremely furious and being ignored as if I am not a customer is just adding to my frustrations. They also do not have an international line so I cannot call and speak to a person. I cannot express how absolutely furious I am at this negligent, poor service. MTN you are disappointing and the sad part is I used to work with you whilst I worked at Primedia in SA. I can make this go very public if I want to, if I am not assisted soon and with prompt, great service...