utility warehouse debt/legal fee ??

louise1984_2

I live in a rented flat and the current supplier is utility warehouse for gas (prepayment meter) and electricity (monthly bill) for the first few months I paid as the bill came in, by card over the phone, and then they wrote to me and said I would have to pay £100 deposit if I wanted to continue doing this or alternatively I could pay by direct debit and I wouldn't have to pay this.. I didn't pay my november bill by the date requested and they sent a reminder letter, so I called and paid over the phone, set up the dd on the phone at the same time, was told that the bill that would be due on dec 31st was already generated and the dd would not be set up in time for that bill, so I paid that bill at the same time, so recently I have received my jan bill which is due to leave my bank on jan 31st by dd, and it has on it an amount of £35 stating it is a debt/legal charge, I have no idea what this is as I have no arrears with them... I have emailed as their phone lines were shut, have had no response yet... Anyone know?