Upset and disappointed customer

Last year i took a contract phone with mrp mobile, i was advised that I will be debited my normal instalment in Jan and Dec they will debit the admin or connection fee something like that which was debited in Dec now I got a call from their call centre saying R250 will be debited thiz month which include qhat i have used for the month and I called and requested for a limit on both data and airtime. My ref was *** this is a day light ******* I regret taking tbis contract honestly. Why is the amount now different to the initial amount for the contract it is the 1st time taking a contract with them and I will never refer anyone to take the phone with them NEVER