Extra charges on monthly bill.

I upgraded my contract in February 2019 and I was told that my monthly premium will be R189. I have now received my monthly bill for the month of June it the total owing is R397.49. Can somebody please explain why my bill is so high and please don't tell me you gave me extra benefits which I didn't ask for and now you are charging me for it because if that is the case please don't give me anything extra than what I have app**** and signed for.