I have 300£ on credit with Shell from overpayments. They've just put my dd up to 75£ a month. My bill is usually about 46£ (single person). I'm annoyed I can't just opt out of paying for a while & they drain down my credit. As it is, the best I've been able to do is reduce my dd but the lowest they'll let me go is £55pm so I'm still overpaying!