Swim swap disaster

I never thought making a swim swap with MTN was such a hussle. I phoned customer care staff more than five times and none is willing to assist. They asked me security questions, they needed 3 frequently phoned numbers which I gave them and they insist that the numbers don't exist,I mean really right now? Then they ask for how long have I used the number,I mean its been more than 10 years, how am I supposed to remember the exact date. I tried to explain to the consultant IDA SALEM that for sure the numbers I gave her are right, she insisted they are not. What must I do now? I really hate MTN,I'm thinking of porting to vodacom again..