I recieved four calls from 678-594-4800. They hadn't left voice messages. So, I googled the number and it says "Carmax".

its carmax auto company.  i guess they changed their number from a 770 number to 678.

I received 3 calls from 678-594-4800 with no voice or other response from the calling number in one day (today).  Called my local CARMAX store and spoke with the business office.  They advised calling their Corporate Offices.  Can't do this until business hours.  That phone number is 804-747-0422.  They are located in Virginia

Got five calls from this number today with no message left.

I received multiple calls and a text asking me to please call a.s.a.p.