The Idle Biker

Call them and ask them what they want.
I think they just mean the invoice from the repair shop and for the parts.
It could be that they sent their letter before your invoices arrived with them and the correspondences just got out of step.

Based on what I had repaired on my car in similar circumstances I think you've done all you need to. You may just have to add that you are happy with the repairs (if you are) and that the claim can be closed.