FTC Targets Invention Promotion Firm. Demand written proof - including specific examples. They love to send out press-releases telling the world about what they've done. Most successful inventors have many newspaper stories written about their inventions. The more publicity they get, the more sales they generate.
Publicity also helps inventors find investors.
Ask for proof. If they do a poor job, give you incorrect information about complex patent issues, or charge too much, then you can complain to their registration authority, and their registration can be revoked. When you deal with someone who is NOT registered in Canada or the U.S., there is NO guarantee of accountability. If you're not satisfied, there may be no authority you can complain to.