Highly unlikely if Colloidal Silver had no effect then I doubt that cinnamon would be any more effective.
It sounds like they are highly resistive to antimicrobials.
Cinnamon essential oil might be more effective but even that might not be enough. The essential oil has to be used very carefully because it can have some unpleasant effects on the mucus membranes and skin. Mixing it with food would be okay or adding a drop to a capsule or mixed with other oils. Never swallow it neat because it can cause bad swelling.
Your best bet might be bacteriophages. These are viruses that attack and destroy bacteria. Every bacteria they infect they produce more viruses and destroy the bacteria when they release new viruses. When the bacteria are all destroyed they cease to exist. You would probably have to import them from Georgia Eastern Europe. It might be worth investigating.