I didn't answer, I don't know what they wanted. They only rang once or twice.
All I can add is this:

it came up on caller ID (CID) as a checkmark, followed by +17865400255
under that, on CID, it was again listed as 1-786-540-0255
9Jan2015 151PM

Looked really strange on CID.  I've never seen any number displayed this way before now. Another person said they're in Florida(I think they said that). don't call back, you don't know where you're calling, don't get hit by any possible charges.