Two sales, same repeat buyer. You generated two labels, one for each sale, but only used one label by putting both purchases in the same package. Package was shipped and seemingly received.
Did this repeat buyer ask about the second order, or did they recognize they received both purchases in a single shipment and are happy with that?
You would have an issue if the buyer opened an INR claim on the unused label because you would have no way to prove both purchases were in that one package.
Otherwise, I can't see where there would be a problem. eBay sees the order as having been shipped. The customer received both items they purchased and appear to be happy with that. Unless the customer complains, what does eBay have to get upset about? They collected their fees and the buyer is silent/happy. If they raise a stink, they will lose the fees paid when the 'unshipped' order is cancelled and refunded. That's not good for them - better to just let it be unless the buyer complains.
At best, you've lost the postage paid for the unused label. A very inexpensive lesson, actually. And it's not likely that your customer will complain to eBay first -- it's been my experience that repeat buyers tend to contact the seller first if they have any concerns. I would assume they do this to retain the relationship they have or are developing with the seller. I have a noticeable number of repeat buyers, and a good percentage of those are 50+ sales repeat buyers. I cannot remember a single one of them not contacting me about a problem (usually a USPS-related problem). And in many cases, when I offered to refund the delayed shipment (especially if it was weeks overdue), I'm told "Don't worry about it - it will show up eventually, I'm sure".
Don't fret over problems that have not actually materialized. If the buyer is happy, eBay is happy, especially if that buyer continues to buy. Spend that energy finding new items to sell, new ways to sell it, and keeping your customers happy and hopefully coming back for more.
-Bob.
