That's an interesting reply, RJ.
I must say I was minded to agree with Ferret's assumption (based on experience both of my own travel and of others I have worked with as clients or voluntarily) that an IRCAS claim can be disregarded if the Claimant (the TOC) conceeds the Claim.
Indeed I'll go further, and assure any passenger that if the TOC has conceeded that the claim is void, then whatever might be said by any other party, while the Collection Agency may still be in posession of an instruction to peruse a Claim, if the debt to the Claimant has been settled or cancelled, then the debt to the Collection Agency has been settled or cancelled; even if they don't know it.