Be careful that they dont use hidden-city ticketing.

For example if you are flying NYC-BKK, they will book you a SYR-NYC-BKK ticket which may cost less with a stopover at NYC, but you will be outta luck when you show up at NYC trying to check in

I would be very wary of a random website "calling someone at the airline"
On the other hand, they may have access to contracts, and may be legit.