Damaged Items

I purchased some postcards, yesterday I got them but the envelop was bent and it damaged the postcards. Apparently it was done through the mailing process.
I never had problems with the seller previously, what you would you recommend?

Contact the seller and explain how they were received. He should be willing to work with you. Especially if you have had good transactions in the past.

Did the seller use any form of cardboard / stiffener protection? Even if the sender did, it's probably not their fault.

I have noticed even if the sender uses cardboard and pays the extra postage fee for non-machineable service, the postal service may still try to process mail through the machines. From a few pieces of mail sent back to me due to bad addresses, I can see that the mail that was hand canceled at my local post office was then sent to a larger sorting office and postmarked again by the processing machines. Luckily, I'v only had one out of thousands sent in which the machinery mangled the mail.

If the seller exercised reasonable caution in the shipping he may have a valid claim with USPS especially if he requested hand cancel and paid extra. However your issue will be if we're dealing with one of a kind cards be prepared to accept a refund or other cards.
Tom

Paid extra for a hand cancel ? I've never heard of this. My local Postmaster lets me hand cancel my own shipments.

I'm thinking "paid extra" refers to paying a nonmachinable surcharge. I suppose I shouldn't rule out some entrepreneurial clerk trying to get a little cabbage for hand stamping, though.

I don't think paying a nonmachinable surcharge gets you any ability to make a claim when USPS decides to find out whether the piece is, in fact, machinable.