SIMCO INTL EBA Clearing S.A.S is the provider of the the infrastructure behind the inter-bank system that is used for SEPA payments. It stand for Euro Banking Association.
So an "EBA ID" is probably a payment ID from their systems. If you're expecting a SEPA transfer, but it hasn't arrived, you can ask the sender bank for this ID so that bunq can then look the payment up and see what happened.
