Hey Howdy Hey Jessie and welcome to planDisney!
Thank you so much for stopping by with your question on Theme Park tickets, your
MagicBand+ and
My Disney Experience account. There is a lot to unpack to get things situation but should be an easy process so let's get to it!
The first thing to note about your MagicBand+ is linking this to your account. MagicBand+ can only be linked to one account and if the account you would like to use it under is yours, you should be set with your MagicBand+. If you did need it to be linked to a different account and already is linked to one, then this could be taken care of by a Cast Member either by
calling Disney at (407) 939-4357 or by directly working with a Cast Member once onsite for your vacation.
It sounds like the issue may be with your ticket. When someone buys tickets for others, they are the ones responsible for assigning them to the right members of their travel party. What I would have your sister do, is log onto her My Disney Experience account, go to the "My Plans, Reservations and Tickets" section and click on the heading "Tickets, Passes & Memory Maker". Once there, she should be able to see all the tickets purchased and the members of the party they are assigned to or not. If the tickets are not assigned, then she should be able to click on the assign drop-down menu on the right and find your name and character icon to assign the ticket to as long as you both are connected and sharing plans. Once the tickets are assigned to an adult's profile, the owner of that profile will be the only one that can reassign the ticket if needed. After she goes through these steps, then it would be in your court to check on your account.
The next step would be to verify the ticket your sister purchased, was assigned correctly to your account. You would do this by logging into your My Disney Experience account and going through the same steps listed above in the "Tickets, Passes & Memory Maker" section of your account. As long as it was assigned correctly, you should see your ticket there as well as the details of it such as the number of days and any options such as Park Hopper Option. As long as you now see your ticket there, your MagicBand+ should work with your account and linked ticket without issues.
Hopefully following these steps gets your ticket situation resolved. If you continue to experience issues getting your tickets to the right profiles, you can reach out to a Cast Member at (407) 939-4357 and discuss this with them. They should be able to take care of this quickly. Please feel free to reach back out with any further questions you may have, we are always happy to help!
Have a Magical Day,
Nick