If a deposit has been attached to the incorrect quote.
In Sales Ledger, Deposits File - you would have to locate the transaction. Note to filter contains on the name maybe easier.
Clear the fields STATUS to blank. Once updated the refund can be processed. (You may need to update or change the refence field MISCREF)
Note: You would only do this if the deposit doesn't show on the vehicle it thinks it is linked to.
See article to process refund: https://learnsystime.auxosoftware.com/a/solutions/articles/51000204443?portalId=51000016179