Cell C sim ported to MTN it self?

My Cell C sim card was ported to MTN yesterday evening , MTN customer service could not help because porting department closes 5pm so they told me i need to phone in next morning when they are open, then how did the port process started at 5:14pm? and later that night after 9pm my sim card was ported. without me requesting MTN for this port how can MTN allow someone while your PORTING department is closed for the day, to port my number? is there people inside MTN who is doing this? even next day MTN customer service was not help full at all, they could not tell me how did this happen or who did this, and if i would like i can go to the police station and make a case of *****. but if im not sending a port request from my cell c number which im using to MTN to ask for port then who did? and how? Is this so easy to port someones number to MTN? I see whole lot of people having the same issue and complaining here , but what is MTN doing about it? how do a person prevent this to happen again??