How do you get in touch with actual Customer Service?

About a month ago I ordered two pieces of furniture from a 3rd party seller through Amazon. There was a 10% discount for ordering two. One of the pieces arrived a few days later. The other one still has not arrived.

In the meantime I found a different piece of furniture that works better for my space than the second (delayed) piece. I want to cancel the second piece before it ever charges/ships. If it arrives, I plan to return it.

I try to cancel... error message: you can't do this due to the 10% off deal. speak to customer support.

I click customer support, I click on the item under customer support..... it takes me back to the cancelation page. It's basically a loop.

Is there a way to speak to an actual human being in order to get customer support for this item? Am I missing something?