PASSING THE BUCK! R20 000 ****** form my account!

My cell phone provider is Virgin Mobile. In December 2014 I received an sms from MTN informing me of a port request. I was away on holiday and outside of signal so by the time I was able to respond and call Virgin mobile, (my service provider) the port had already been initiated. This was done by both Virgin and MTN WITHOUT MY PERMISSION. MTN should be able to provide me with the evidence of my permission. They can't because I never authorized a thing!<br> I want to know who at MTN authorized this action. It resulted in a blackout of my phone for 3 days in which time a total of R20 000 was removed from my account using 'instant money'.<br> MTN has investigated and not provided me with sufficient evidence of port request authorization. Instead they have passed the buck and claim that I made my Std Bank security info (pin/password) available and that is why money was ****** from me.<br> There is a simple order of events here: as a direct result of MTN authorizing the port, my account was made vulnerable. The big guy needs to take responsibility and show me evidence. Please! I want my hard earned cash back.