billing issues

Rian claims you don't have a contract, you pay your internet as you use it, i did not use the month of Jan, which is something I do often as i don't work, They have billed me for jan and Feb with no reason at all.

I have done this so many times before and i know i have never been billed for the months i did not use.They they are coming up with lies so say I have used the internet but cant provide the proof, you cant say its a no obligation contract and then you are holding me on, You disconnected the line as i don't have access to it which is rightly so its a prepaid month to month.Please i dint need anymore explaining , clear this billing so i can pay for my internet