These days, your strata committee can’t unreasonably refuse you the right to have a pet (or pets). If your foster cats are confined to your property and not bothering anyone else, then I think it would be unreasonable to expect you to pay $100 for each and every foster pet.
You asked. You paid. They didn’t refuse. If they decide to take you the Tribunal I think you’d have good arguments for saying you thought their response implied permission. But in the first instance they would have to send you a Notice to Comply – which refers to compliance with a by-law that is no longer strictly legal. So if it were me, I’d be taking care of those foster cats and not applying every time. You already applied.