Seconding this! My experience is from flat-sharing only, but if the culprit had to pay the difference it always worked. But also try to find out what'd be the least annoying for you in the long run: living with this unresolved situation and possible consequences like the interwebs being shut off or whatever could happen, or transferring everything to yourself, no matter how annoyed you're about the need to do this right now. *more sympathies*