If you wants a delete voucher and it get stuck in BUSY while deleting,you need to check these things:
Step 1:First you will have to close the BUSY from task manager,
Step 2:BUSY set as compatibility mode,
Step 3:Re open BUSY and company,go to the transaction,
Step 4:And open that voucher Again,which you wants to delete,then delete again,press f8 then it will be resolve.
Step 5:If still showing issue then take backup first of your company,close company,then re index data base run,
Step 6:After cpmplete this process then re open your company then check it will be resolve