They probably just blew off your offer for help, no harm. They have their processes, however awful they are.
What you can do (US List, other countries may have other relevant docs):
- Gather your W2 or paystubs for every job you have had for the last 7 years.
- Gather and be prepared to provide all your addresses for the last 7 years.
- Gather your tax returns if you were self employed for the last 7 years.
These are all things I was asked to provide for my last background check. Having all that handy is very beneficial if/when they ask. Don't bug them with these though, wait for them to ask for them. But sometimes these can be hard to find on short notice. In the US you can also go to a local IRS office and pull these records, unless the online system is back online.
That said, my last background check was far more thorough than any I have seen before, including government ones. Apparently fraud during background investigations is on the rise. This may be one reason they have not contacted people you provided, they want to try their own independent routes first.