Checked 'Create Debit Memo from RTS Transaction' at supplier site level, still no debit memo created

Hello,

We enabled a supplier for ERS ( pay on receipt at supplier site )

The site is pay site and purchasing site.

we created a requisition, purchase order and receipted it.

Ran 'pay on receipt auto invoice programme' -- An invoice is generated.

Now we did a return using IPROCUREMENT ( we do not use Inventory, so none of our users have access to the receipting screen in core purchasing )

WE ran the pay on receipt auto invoice programme again.

The debit memo is not created.

Please advice, what is wrong here ?

Thanks in advance,

Kris