Angry customer

Rain disconnected my service after I made payment on the 31st of January, having not used their service in January though I would pay for February but after making a payment they disconnected my services and ask me to pay for February, I made payment and called why I was billed twice in the space of 2 days. Their consultants say I'm on a month to month basis but I was billed for January even though I didn't use their service