How do I find the business address of someone I have hired?

I recently hired Sky Roofing and Propert Maintenance based in Chesterfield and I am wishing to write to them to open a complaints case. They don't seem to exist anywhere and the only trace of address information is here on RatedPeople where they have the verification stamp. The business is not responding to my emails, calls, texts on the matter so I am really looking to take this further now. Thanks for any help in helping me resolve my case