Do a mutual on the first and give a polite explanation if you wish. There is no point in making an issue out of it and keep in mind for first timers eBay can be very confusing. On most ecommerce sites the situation would not be any problem for either the buyer or the merchant.

"What else could I do? I had no trade so I became a peddler" - Lazarus Greenberg 1915
- answering Trolls is voluntary, my policy is not to participate.