I received 4 letters to my home today addressed to someone I’d never heard of. They were from a mobile phone provider so I opened them. All 4 were opening a sim only phone contract for 4 different numbers. I contacted the phone company who said they’d passed it to their fraud dept who have up to 10 days to get back to me. I’ve checked my credit report and there is nothing new on it. I’m really worried about this. Does anyone have any advice?