I had the same problem as you, I tried ringing the phone number on the letter for days. I left my phone number on the ans machine but they still did not get back to me. So I sent everything they requested and waited. After about 2 weeks I received a letter asking me to contact them on the number above on the new letter, only problem they had forgot to write number on letter. There was a fax number so I just phoned the fax number changed the last digit and somebody answered the phone. The person I spoke to gave me the persons number I needed to speak to. I phoned the person and managed to speak to them. I know a lot of people on this site speak to some nice members of staff but not me. All he seemed to do was ask me questions and dates he even knew when I had been on a holiday abroad. He knew about everything my partner had by post to my address mail order, credit card, etc. He also knew about my council tax only being in my name and other things. Im also worried how this is going to affect my job as I work for the DWP. He said he was unable to let me know what is happening till next week as he was only covering for somebody on holiday but he would be telling her to cancel my money and she would be getting back to me. I've decided to come clean and tell them everything just worried sick I will lose my job. Don't want to scare you but when you speak to them be careful what you say because they seem to already know the answer and want to catch you out. Best policy I think be honest. Hope it all goes well for you.