"So World Nomads hires TripMate to process their claims?"

Yes

I believe this is similar to how the US health care insurance provider's work.
When your doctor requests a procedure like an MRI, it first has to go through a third-party approval.
These third-party companies get paid by the health insurance companies, like CIGNA, based on the procedures they deny.

I suspect that Trip Mate must have a similar deal with World Nomads which is a Nationwide Insurance company.

If all else fails, I will be contacting Virginia's State Corporation Commission's Bureau of Insurance to file a complaint.