HMRC says they have no record of my self-employment

I became self-employed in 1983. I returned self-assessment tax returns for years until I was told I no longer needed to. I was VAT registered from 1986 to 2011 until I was told my earnings were too low. I've had no income since 2013/14 and I've been living off my savings since then. I am registered with Govt Gateway and I have a UTR. I want to make voluntary NI contributions going back to 2006/07 but the cost of filling the gaps for all the tax years since then is for class 3 NI only, with no class 2. HMRC have said they have no record that I have ever been self-employed. I sent a letter two months ago to NI Contributions Office with proof of self-employment (copies of tax returns, VAT registration and invoices) but they have not responded. When I phoned they said I need to update my details but didn't say what exactly. I moved house in October 2013. Nearly all my self-employment was when I lived at my old house. I tried to re-register for self-employment online (not form CWF1) but the application has been refused: "We are unable to process your application because the address provided does not match our records. WHAT TO DO NOW You will need to check or update your address before resubmitting the form." The online re-registration included correct new and old addresses. What do I need to do now?

Hi,
You will need to contact the National Insurance department for details on if and how voluntary payments contributions can be made.
You can contact at National Insurance: general enquiries.
Thank you.