Mtn data contract

Mtn service champions are useless We took data contact with them which was supposed to be 10gig anytime and 10gig night Express,at first I received 2,5 gig as prorate because it was in the middle of the month then come to my provision day I only received 5gig anytime and 10gig night Express,I called the so called service champions as they called them self but to my surprise she can't even see that the data was not loaded as per the contract, she told me that I have 7,5 gig anytime which is left from my 10gig provision for this month,,I tried to tell her that 2,5gig carried over and 5gig is what was loaded, Mtn keeps on promising the service that they can't render,u apply for 10gig but u receive 5gig yet they want you to pay the amount that we signed for while they don't offer the service as per the contract that was signed What on earth is this? Can someone from mtn explain this.