Data Depleted before the upload date

Your data will be depleted in the next 48hours (that happens every month on the 10th). Which means my data gets depleted on the 12th whereas I get uploaded on the 14th. This has been happening ever since I got this stupid contract with MTN. I have phoned for about zillion times and every one keeps saying the same stupid thing that I am using up my data coincidentally on the same date which is the 12th of every month. PLZ whoever can assist help fix this thing. I have phoned for so many times already. SOmebody PLZ help atleast so that I can see of this stupid contract and I wont have to have anything to do with MTN.