I stopped at Home Depot on Tuesday afternoon and they had a mixed bag of tropical hibiscus, white single with red throat, yellow single, and even a red that all had a tag that said Elephant Ear. What a laugh.

Compare your pic to the AHS pic. Note the differences between the petals and flower formation. Also, note the difference between the leaves. They look very different. I'm guessing someone mis-labeled the plant you bought. When you have many varieties, it is so easy to get the names mixed up.

The comparison between the AHS pic and mine, was what made me wonder. Mine is actually creamier than it looks in the shot I took. Depending on the site, the same one that AHS has up looks more or less white. The biggest difference to me is the color of the leaf. Even the written description states that the leaves are very dark green.
I bought mine at an independently owned nursery. They had several pallets of them, all labelled the same way. I think their vendor messed up. It's a pretty hibiscus, and I can enjoy it just fine, but I really like true white blooms, especially, as it is planted next to a bright fuschia one. What I have to remember is that most other people don't think of those things when they admire a garden. They just see the pretty flowers as they are and appreciate them as they are.