based on common name, website, email addy etc. But sometimes it doesn't happen properly and a second profile gets set up by mistake.

If you come across a second profile for the same person, submit a problem report to get the profiles merged.

I wrote a review a while ago, and instead of adding it to the provider's existing profile, a new profile was created.

Since then, I put the provider's ID number next to her name when I write the review, and that seems to have solved the problem, especially if she has a fairly common name.