You need to call back and ask for someone specifically in Guest Services. We have been going to Disney every year for the past four years. Two out of those four years, we have had some unexpected issues that have come up in which we needed to extend our payment due date. Both times it was no problem. In fact, my last trip, I think I payed it in full only 12 or 13 days prior. They were very understanding and cool about it. They had told me, that it is not their policy to extend the payment date, however if a family has already put down a decent deposit, they are not going to go in and cancel your trip. It's not an automatic or electronic cancellation. Someone in the Accounting Dept needs to manually go in and cancel you out. They told me that they just made a note in my account of when I'd be able to make my final payment and to ignore any further cancellation notices that I'm sent via email. You will be fine and have a great trip!