Billing Mess

I was \sold over"to Altech Autopage by Nashua Mobile in 2014. I used to pay my bill by direct debit order each month. However it appears my banking details were not passed onto Autopage. For about 3 months I never received any invoices and no debit orders went off my account until my phone line was soft-locked and eventually disconnected completely. I contacted Autopage several times requesting for invoices and provided them with my banking details but nothing happened. They however managed to \""remember\"" my email address because they have since been sending me letters of final demand (even when I personally have called them several times and provided my banking details to debit my account). I eventually cancelled my contract and went prepaid. I have asked them for invoices etc and nothing seems to happen. I will not even go into the details and pains of trying to reach them telephonically - that seems to be well-documented. My line is now a prepaid"