Caller ID "Customer Service", Does not leave a message. Internet search indicates the number originates in Polk County, Florida. Cellco Partnership DBA Verizon Wireless.
Caller ID says "Winter Haven FL". They leave no message.
I call back after hours (using *67 to block my number). I hear the following, "Hello and thank you for calling. If you'd like to be placed on a Do-Not-Call list for the number that called you, please, press 1 now." (I never go on their DNC list as it can actually make things worse).
So they spoof their caller ID and fail to identify themselves on their message. I'm guessing this is some kind of SCAM.