Incorrect contract and no one will help

I got a 100gb black Friday special contract with MTN, for some reason they put me on 500MB. I went to an MTN store and called the call Centre they are both unable to help and I was told to call Mondo. Called Mondo and I was told I wasn't the only one with the problem so they are working on it I haven't heard anything from them and don't even have a reference number to follow up on. The lady at the store told me it could take up to 2 months to get it sorted. What nonsense is that. MTN fix this problem or cancel my contract immediately.