I have found, and I believe others have, too, that liquid from wordup needs a bit of time to sit to fully flavor up. They make it to order, so your order was made shortly after you ordered it. I have some lime that I ordered in my first order from them back in August that has quite an impact now. It's like it mellowed and settled into what it was supposed to be. I'd say this difference was at least two weeks from when I first tried it. I know it's tough to wait. But it might be worth it. And at the end, like Brian said, you can trade or sell it here.
You also might try getting some menthol crystals or DIY no nic menthol liquid. Some people find that when used very sparingly in any flavor they get, it adds to the throat hit without overpowering the flavor, say at like two drops per 10ml bottle. You could add much more than that, of course, to get that menthol you're really looking for.
Do contact Jeffrey at wordup. I'm sure he'll have some advice for you. But, I agree with Brian, vendors don't typically do returns.
You'll find something that works, soon I hope!