Keep your tracking number, keep your order number *helpful tips*
It wouldn't be right if I don't share real life experiences.
1. If you sell hard tickets, write down the barcode on the ticket and the initial order/confirmation number from the primary order.
Buyers getting in the habit making false claims and you're going to need the information to back up that they were legit valid tickets.
2. Keep your tracking number. I got an email from SH talking about:
I HAVE ONE HOUR TO SHIP TICKETS; when I shipped the couple days before. I furthur researched and saw the label was changed. If I didn't have the original tracking number it would have cost me hundreds. I gave the SH phone rep the original tracking number and he updated the order. He didn't know why it changed. I have asked for it to be looked at and (SH still doesn't know why label changed and failed to follow-up with me as they said they would).