Contact the vendor?

I ordered them from Home Depot, so I'm not sure they'll be much help. I'll give it a try, though. I was also thinking of emailing Encore directly.

Update: I contacted Encore and they identified my plants as Autumn Rouge from the photos I sent. Home Depot offered me a 50% refund if I wanted to keep them, so I accepted. While I was at HD today, I noticed they had Autumn Sunsets (with blooms so I knew I was getting the right plant) for half off, so I snapped up three 3 gals for $40 total! Autumn Sunset is quite similar to Autumn Embers from what I can tell so I'm a happy camper.

There is certainly an advantage to the suggestion of buying plants only when they are blooming. I am glad that HD made you an acceptable offer and am glad that the plant is a rebloomer. I once bought a rose that blooms only once a year (so it is not a rebloomer) and I purchased it while it was not blooming. Weeeell, I had the same issue as you did but the nursery did nothing because I did not contact them "early enough" (I had to wait until Spring of the next year to see that the blooms were the wrong color). Not even a discount on future purchases. Oh well. Live and learn... I learned to be more cautious with shrubs that bloom only once a year or that are not blooming until after the plant nursery's warranty expires.

Enjoy your Rouges and Sunsets. I have an Autumn Royalty. I considered some of the orange-y ones but had a hard time finding a good spot for the orange blooms, which is how I ended with AR instead.

Some of Home Depot's plant providers are notorious for labeling plants incorrectly. At least in my region.