So a Classic Era server? If that is the case, then you cannot use the Transfers on that type of server.
The Character Transfer service is not available for WoW Classic Era realms, including Season of Discovery, Hardcore, and Anniversary Edition realms.
You can put in a refund request for the Transfer package here on the website:
link: https://us.support.blizzard.com/en/help/product/wow/166/1153/solution
Just click the blue Contact Us button and let the system check for your purchase.
If you are referring to a transfer within the Classic Progression servers (currently Classic Cataclysm), then the advice from the other posters to check the status of the purchase and wait for it to clear would be the correct course of action.