Not getting what I'm paying for!!

We took out a wifi contract 31 of December. The sales person advised that the contract is a 20Gb day and 20Gb night, with a bonus 20Gb day and 20Gb night. That's 40Gb day and 40Gb night. On the 12 of January 2018 our new data was loaded and by the 22nd of Jan we have reached our limit. Mtn customer care informed the the bonus 20Gb day and 20Gb night was never loaded. Ive been contacting the Mtn store daily to rectify this issue. Sometimes calling 6 times a day as the sales person will call me back because he is busy and he simply don't get back to us. I went to another mtn store which informed me that on the system it reflects that we dit not receive the bonus 40Gb. Back to the previous store, they also confirmed this and said that alot of clients does not receive the total package and that this is an issue. I called again this morning and they are back to the story that we did receive the full package. Even one of Mtn own employees confirmed that he also does not receive the full package. I'm going to cancel this contract and will never do business with mtn again and I will also advise all people I meet not to do so. Nobody is able or willing to assist with this issue! We are paying for a product that we cannot use! It's never a pleasure phoning mtn as nothing gets resolved!