I think it's a credit card merchant fee scam. They use a number of different phone numbers to attempt to bypass call blockers & also waste time by leaving robo VM messages.
Recent Complaint Activity for (720) 697-1353
FTC Complaint reported as spam
06/21/16 10:00 AM
An EveryCaller user reported as spam
06/21/16 09:51 AM
An EveryCaller user reported as spam
06/21/16 09:30 AM
An EveryCaller user reported as spam
06/21/16 09:15 AM
A Call Control user reported as spam
06/21/16 09:02 AM
An EveryCaller user suggested caller name as Better Merchant