Credit Cards Stolen

My debit card and credit card were stolen at ballpark today. I called my bank within an hour. They didn't find any illegal charge and just cancelled my debit card. I then called my credit card company; two charges (total about $500+) had been put on my card. The representative transferred me to the fraud department, and I was told that they would cancel my card and started an investigation. I will receive a form within a few days and I need to fill and return them ASAP. Other than that, I was told I don't have to do anything and do not need to pay these two illegal charges.

Is that simple? Do I need to take any extra measures? Anybody with similar experience?

Sorry, I can't type in Chinese on this machine.