We're with EDF and they keep deciding to put up our monthly Direct Debit. This then accumulates a large credit on our account, which necessitates a lengthy and argumentative phone call to them demanding it be reimbursed. They always explain it's 'to tide us over for the winter'. But we use oil for heating, and the electricity doesn't vary much with the seasons. They're always furious if I insist on having OUR money back. But it's the law, they can't keep money one doesn't owe!