Posted batches cannot be unposted or deleted.

The only way to remove a posted batch from Journal Entry is to restore to a backup copy of the database from before the original post and post it again. If you decide to restore to a backup copy of the database, all the data that was entered since the backup was made will have to be reentered in each of the subsidiary modules.

You can reverse a posted batch to zero out the original posted transactions in the General Ledger accounts, but both the original and reversed batch will remain in the system. See: Does reversing a batch undo the posting process?
In order to show fewer batches in the list,
Filter Journal Entry screen to display Open batches only OR check box to display batches created by user only