Used stamps exchanges.

Hello to all. Today I received a letter from Canada. I opened the letter and inside there was only a piece of yellow paper and a note written "Hello, Here are my 100 stamps as my trade to you. etc etc.But where are the stamps?

Sorry, I misread the question. The stamps were going/went to Italy. Ignore my above post.

CA - 1182

which is the country destination of that the shipment?

Hi, That letter was from me. Well this is a first for me. No, I did not forget to insert stamps as I have to weigh each letter before posting. Has the envelope been tampered with? Of course if there are no stamps then it obviously has been tampered with. You mentioned there was a yellow paper inside. I do not use yellow paper. I use a preprinted note on white paper. I will resend with 100 new stamps and I will use the same number to register. (CA-1182) Since I don't keep track of what I send, I will be sending random picks.
Maybe you have a gremlin in your post office. Has this happened before to you?