You don't be have to call. Do these steps first:
~ go to DISNEYgiftcard.com and consolidate your balances on one or more cards. Maximum on 1 card can be $1000.
~ then, go and purchase your tickets breaking up into more than one purchase if necessary. You can only use 1 giftcard per transaction.
~ if you don't want to use the giftcard website, you'll have to call and read off the info from each card.