Hi Melissa!
Welcome to the Disney Parks Moms Panel! Are you excited for your upcoming Walt Disney World Resort Vacation?
Unfortunately there isn't a way to make payments on an upcoming reservation or vacation package online; there used to be a way, so you're not miss-remembering anything if you used that service in the past. However you are more than welcome to call the main reservation line to make payments as many times as you wish, paying whatever amount you'd like, towards your upcoming trip. Their number is (407) 939-1936 and they are open from 7 A.M. until 11 P.M. EST seven days a week.
While you won't be able to pre-pay for the charges that are yet to happen, like souvenirs or really cool experiences at Disney Springs, you can pay off things that you've added to your reservation or bundled into your vacation, like
Dining Plans,
tours or
speciality cakes.
Another way to sort of 'hack' pre-paying for any Disney vacation is to purchase
Disney Gift Cards. Disney Gift Cards can be used at almost any and every location across Walt Disney World to pay for any and everything you can imagine, including the gratuities left on meals that were purchased with a dining plan. You can find these cards at grocery stores, big box retailers, warehouse clubs, drug stores and more in your own hometown, and you can either call a payment in with these cards or save as many of them up to pay off your balance upon arrival. Disney Gift Cards come in dozens of great designs online, and they are a great way to allow kids to manage their own spending money.
I hope this helped, Melissa, and We'll See You Real Soon!
~Kristen