According to a post on "Whycallme," this is a scam attempting to get credit card information.  Here is the link:
http://www.whycall.me/779-803-0937.html.
According to callerdb.com, this number has no specific location and is likely spoofed.  
Put it all together and it spells SCAM.  Anyone going to these lengths to hide their identity while asking you personal financial information should be ignored and blocked.

Hope this helps.