+1 for "change up the call"
If you wait a couple of weeks and change to a different sound you can call in the same coyote again this time of year. That's not saying you will call it in, just saying you can.
Something else that can help is to be calling the same area but sit in a different location if possible, maybe just 50 or 100 yds away from where you were last time.
You mentioned that you didn't know if it saw or smelled you? Try setting up in a spot where you can see downwind of yourself or the call. That will eliminate alot of coyotes smelling you. Coyotes can also smell your tracks (where you walked in) and leave..........Ive seen it happen a few times.
Good luck and good shooting!