Coin bought in an auction was not as advertised.

[machomagnolia]

I bought a 1928-P Peace Dollar by auction, and had it sent to my mother.  She told me that she received the coin, and it was as advertised.  When I got to see the coin 6 weeks later, it was actually a 1923, not a 1928 (verfied by a coin dealer).  I contacted the seller, but a return and refund was denied by the seller.  Do I have any recourse?  I already gave him positive feedback  based on my mother's report.  If the seller is fair, and takes the coin back and gives me a refund, I am fine.  If not, what else can I do?  The 1928-P Peace dollar is very rare and expensive, much more so than the 1923 Peace dollar.