Who called from 3134427340

This number 313-442-7340 called my land line with an caller ID of RETURNEDNUM and left no message after I didn't answer it.   Must be more spammers.

i answered and put on mute immediately.  id said "detroit"
nothing on the other end.
i called the number back on magic jack and a male voice said "the number is not allocated".  Doesn't sound like a recording that you would normally get from any phone company.

Called my landline, no message, came up as, "RETURNEDNUM"