MTN PROMOTIONAL AIRTIME A SHAM

I bought R150 airtime with the aim of getting data bundles. I recharged my phone and checked the balance which was R600 and I did not understand that. So I proceeded with trying to purchase the data bundles and the reply was insufficient funds. Even tried to get the promotional 2 weeks data bundles and that failed as well. After that I was irritated and just decided to log on to the internet for about 30 minutes. I had read that thepromotion is only for 7 days so I was now stranded without using this airtime because I want it to go away so that I can get the correct balance of my airtime that I had purchased. The 7 days end and the balance is R0.00 and I made no calls or downloaded anything just the internet browsing I had done for 30 minutes. This frustrated me and I called the call centre and I learnt that only the R90 of airtime went through since it was 2 x R60 and R30. That made me so mad because there was no way of telling whether one of the recharge entry had failed just a useless R600 worth of ******* airtime that did not do any justice to my intention. I felt so ****** and cheated and wanted to swear somebody's mother out. So please I need a thorough explanation and data.