I actually had a similar thing happen to me recently. I flipped out and called the restaurant to bitch out the manager and felt like a complete dumbass when he told me that credit card companies/banks customarily add in a certain percentage to every purchase from a restaurant so that you won't overdraw your account. So eventually it will correct itself when the charge goes through and (like someone else said) isn't a pending charge anymore. I would check again online in a couple days and if it's still wrong call the place and bitch out the manager.