MTN- Customer Service & number porting

I app**** for a Sim only contract online. The sales rep contacted me to proceed with the application. I specifically stated that I would like my current prepaid number to be on the contract as I have had the same number for over 10 years and all my personal information goes to that number. She then advised that I would need to wait until my sim was activated before I could change the number at an MTN store. I waited 48 hours as requested. I then went into the MTN store and they advised that my sim still was not activated - I would have to wait longer and then they went on to say that they would be able to assist me over the phone with porting the number. When I called MTN after another 2 days they advised that I would only be able to do it in an MTN store. Keeping in mind that I had already tried calling MTN +/- 10 times. I then went back to the store and they advised that I cannot change the number on the sim now that its activated , if I want to I can phone them and cancel however I will be charged a fee as it is over 10 days since I received my sim card . I refuse to be liable for any costs as I have been given th complete run around. I have phoned the retentions department about 4 times and made it very clear that I will not be liable for any costs and I want it to be cancelled with immediate effect. They then came back with an investigation saying that I did not request that I wanted my current number on the sim in the first place. I am beyond frustrated with MTN for their poor customer service. I will not recommend MTN to anyone as still to date this is not sorted and its been 3 weeks later.