Omg I can't believe you ignored a 11k debt in hopes it would just go away
That said, I would say don't cancel the trip since you're not paying for it. In the future I would suggest that you mention that instead of vacations and such for gifts you would prefer gift cards for grocery shopping or money to pay off your debt.
I would also cut down any unnecessary expense (cable, switch to dial up internet, bag your lunch, don't go out to eat, etc...)
Call Citibank and try to negotiate a payment schedule and a reduction in total debt. Check out creditboards.com