Horrible service!!!

I have a fibre with mweb, my line was disconnected yesterday, i paid on the 30th my next payment was the 16th but the amount i paid on the 30th should have covered me till the 25th, i called the account department and was informed even thought my fibre was disconnected from th 25th of December till i made payment on the 30th i was charged for those days and the money is forfeited. I dont understand how that is possible to be charge for days that the fibre is disconnected. This is a prepaid service, so to my understanding, you use what you pay for. The consultant was not helpful and was talking over me, im very upset with the customer service at mweb