If a low level attacks you and defeats you. You can always hit back from 'Rival List'.
I agree that if a lower level attacks you and wins, you should be able to fight back. This level protection scheme is far too restircitve.
You can't attack if the RIVAL is LEVEL 3 or less... above that there is no level check in RIVAL attack backs,.
Once you have attacked the Rival as many times as they have attacked you, you can not attack them anymore.