It seems to me that if you ask the right questions:
- who holds the copyright
- is the copyright registered
- who holds the rights to enforce the copyright,
and they give their standard, we don't have to tell you till we take you to court BS response, that they are bluffing.
Why do I say this? If you have a documented letter that you know they received (I only send mine registered to this kind of entity), and they refuse to answer your legitimate questions, no reasonable judge will award them more than the $200 minimum.
Now it costs more than that to file. So if they did enough of these, they would put themselves out of business. They might be unethical and scummy, but they are not stupid. They are trying to stay in business as long as possible. A much better business plan is to save the filing fees and collect something from a percentage of those they approach. I would expect that their cost structure is a percentage of what they collect.
So they go after people with a conscience or those who will pay a little to save the potential of big costs down the line.
It's your decision. I am not a lawyer. But I did hang through it for 3 years and paid them nothing, with my eyes open to their tactics the whole time. Their claim on me was something like $42,000 on fifty some mages that my firm used over a less than 2 year period. Did we use them - yes. Did I think we did anything wrong - no. I wanted them to file. I would have rather spent $100,000 in court, on the public record exposing their tactics, and how they mislead us, and how they tried to cover their tracks about the misleading before trolling.
Once they get you in a courtroom, their is no non-disclosure statement in the settlement. In my case, they acted just like a bully. I am not referring to Getty here or LCS, I am referring to McCormack IP Law. When I punched back, they ran and hid.
I don't know the details of your case, and I don't know how much effort you are willing to put out to save the money. But I do agree with Robert. Keep researching this. Do what's right for you.