Jenn cook: I'm sorry you are having such a hard time with your costco link, yes I am the person who had a terrible time too! I am not expert but will tell what I did. Did you have trouble linking your initial reservation? Regardless it seems that by now your new dates and # should be linkable. I would try the Dolphin again asking for the confirmation # that co-ordinates with the new dates. If that # is the same and the Dolphin confirms you are in their system for the new dates then moved on to disney.
I think initially my problem was I did try too soon but then even after waiting the 5 days I was told to I still had trouble. The second time I called Dolphin they gave me a confirmation # that was different from the # Costco had provided. However I still could not link the reservation on line myself. So then I called Disney guest services to get help linking it they told me to wait 24 hours "for the reservation to populate in their system" and try online again. I did, still nothing. So I called Disney again, worse yet this time was the CM who told me I was not entitled to book 60 day FP with this costco package (WRONG!
) I told that CM in no uncertain terms I was done with him because he was wrong and wanted to speak to a supervisor, he pawned me off on to a different CM who was not a supervisor but was more helpful and said my problem would be "escalated" and resolved within 24 hours and I would received an email with details. I was quite skeptical but a few hours later when I checked on line there was my reservation all linked on
MDE! The next day I did received an email from a supervisor saying they had to "manually enter" my reservation #. I have no idea what that meant but it all worked and my FP portal was open.
Other folks here had suggested contacting Disney's tech support or group travel but I did not get to the point of trying either. You can do a thread search using the word "costco" and it should bring up all the posts about it, many helpful suggestions were made.
Please keep us posted.