Calls from 770-450-6233 and 770-450-6234 at various times during the day.  Does not leave a message.  

Have gotten several calls on different days, even Saturday. I never answer on numbers not in my address book. Does not leave message. Annoying

It's Sirius XM. Kept getting calls, so I used a business land line phone and called the number. Machine answered stating" welcome to Sirius XM" I hung up. Mystery solved.

It's Sirius XM trying to get me to renew the account.
They called 4 times every day for weeks. Never left messages.
Finally answered....