Extravagant shipping charge

I purchased an item and already paid for the price.
The description says that the shipping cost will be determined later. I did not ask for the shipping before I made the payment. (Doh!)
The item weighs 55lb, and it is about 17x17x10 size. The shipping box will be about 20x20x15, and the total weight would be close to 60 lb.
For UPS shipping from Arizona to Michigan, the seller wants $150 for the shipping. When I calculated UPS shipping, it is less than $60. Obviously, the seller is trying to make a huge profit from shipping.
Any suggestion to how to deal with this situation?

Thanks.