Hi,
Sorry to hear about your Cocker. Their ears can be sooo frustrating for both the owner and the vet.

A second opinion can be very helpful but please seek out the advice of a specialist (a dermatologist) if you haven't already done so. They can guide you through this very difficult treatment path and tell you when you've done all that you can do. If you live anywhere near a big city, finding a specialist should not be a problem.

Good luck and don't give up!
drphilvegasvet