Square Trade warranty option in auction but not at checkout? How can I get this?

[whitecrystal1]

I just purchased a soundbar and in the auction it showed the option of getting a 3 year square trade warrnty. I clicked the box and placed my bid. I won the auction but the warranty is not being added in the total at checkout. I don't see how to buy it either. I would like to get this if anyone can tell me how. Thanks