This is actually a Sprint customer service satisfaction survey automated call. Nothing malicious but annoying all the same.
Survey
Recent comments:
1
Sep 20, 2011
Called me twice heard the tell end of a computer saying something in Spanish on my voicemail. I called the number back and it said the number is not in use.
Other
2
Nov 13, 2011
3 calls today, no message
Other
3
Nov 15, 2011
I also received 3 calls today. no message.
I called back and the call could not be completed
Other
4
Dec 31, 2011
sprint survey!
Other
5
Jan 18, 2012
Yup...this is just a sprint survey request for any recent customer assistance you've had with them. They usually trigger the call 24-48 hours after any activity with sprint or sprint store.