It may have been a travel company in the past, but in my case it was the Zumba home office calling about my ZIN license & membership. Completely legit.
Called my house twice in the same day. did not answer; they did not leave a message. Called them back. Got a repeating recording saying all agents were busy at this time. Put them on my phone's "Blocked caller" list.
I answered from this number to stop it from ringing. They have called during my children's nap time 2 days in a row. I picked up but didn't speak. They asked for someone who had this number 7 years ago. When I didn't reply, the lady screamed, "I can hear you on the line! Answer me!"