If you would like to confirm that you have received a claim letter, here is a sample template you can use to write an acknowledgment letter for a claim.
To [Recipient name]
Dear, [Recipient name]
This letter is to acknowledge receipt of your letter dated [Date] and the enclosures on [Date of receipt]. We are currently in the process of investigating your claim and you will receive a response once we have some clarity regarding further decisions.
We are investigating our liability and will send you a response with respect to this shortly. This process should take 14 days and any outstanding amount owed by me will be paid by the end of this period.