Do you accept causing the damage?
He is right the extent that he doesn't have to have the work done. If he chooses not to replace the damaged goods then that is a matter for him.
He is also right that he has no duty to provide receipts but only because he doesn't have to do the work.
Compensation is just to cover any loss caused. If a person chooses not to spend that on a replacement then that is a choice they are free to make.
I'm afraid it is just plain wrong to suggest that you can denote what he spends the money on if indeed you accept causing the damage.
Can I clarify anything for you?