That epoxy should have been rock solid in an hour.
one of three things happened with your epoxy...
1) you didn't get it mixed as good as you thought.
2) you got too much of one or the other of one side instead of equal portions of each, thus causing it not to cure because the ratio was off.
3) the epoxy was bad or old.
Epoxy only works on a chemical reaction of the two chemicals mixing with each other, there is not much that will make it not work other then what is mentioned above.
Have you had problems with that same exact epoxy before you did your ears? Or just this time?
Lynn