We had a similar problem at the Coronado Springs Resort. When we got our bill, there was a charge from the Wedding Chapel and we hadn't been near there. Traveling with 50 somethings and 80 somethings, weddings werent in our plans. I'm planning on keeping the one I've had for 32 years. He's a gem.
Anyway we called guest services and explained the situation and they took care of it without a problem.
The KTTW cards are a real convenience but you do have to monitor the statements.
BTW, If you have kids with charging priviledges, I would check the statements EVERY DAY to be sure they're staying within their limits.