If a person tells you that he has posted an Item {But has not} and says it has been lost in the post, and also tells you to put in a claim.
This is Fraud.
Contact the Securities Division of the Postal service and report the person to them.
Give them all the details: re Name / address / dates etc of the transaction.
Postal services etc do not like being blamed for a service they did not supply.
I hope this is of help to you.
Just another way to try and stop the scammers.