Used stamps exchanges.

I sent out an exchange 6 weeks ago to a person. As yet it has not been registered as being received. I fear it has gone astray what do I do about it? Do I send it again? What happens if it does not turn up?

Unfortunately sometimes letters do get lost in the postal system or maybe your partner has not registered it yet.

You can contact your partner and try to find out what happened and if the address is corect.

If the letter is lost by the postal system and if your partner's address is corect, you could consider resending the letter if you want.

Otherwise, the lletter will be considered lost. If the letter is not registered, the sender won't receive a slot to receive a letter back.