Who called from 5123776091

I believe this is part of an internet-based airline ticket scam.

Called twice. Both times it rang twice then hung up.

Left no message. When I called back recording w british accent said person I'm trying to reach is not available and to please leave a message. They called on the same phone I use as an emergency. It is the same phone number the IRS scammers kept calling me on so I'm inclined toward Jeannette's opinion they are scammers.

They keep leaving a weird message that just says good bye.

I answered the phone call.  They just hang up without saying anything