You can write this transaction off by following the steps below:
From the DPS FD Home Screen, select Client Postings.
Select General Postings.
Select OTN as the Posting Type and tick the Tick for Bills check box. You should select a bad debt/write-off nominal.
Complete the remaining fields and click Post.
Allocate the DR and CR figures on the next allocation screen.
The ledger will now be clear.