I am empathetic to your situation, but before you get to upset with Crutchfield, you have to consider what exchanging the piece means to them.
Let’s assume Crutchfield were to take the unit back and exchange it for you.
They would then have to send it in for repair and they would pay the $100.00 shipping cost.
When they get the unit back, they can’t sell it as “NEW”. They would have to sell it as “REFURBISHED” piece.
Refurbished equipment is generally sold at a reduced price. Chances are they would have to sell below their cost.
That being the case, they’ve now lost money on selling you a piece of equipment, plus the shipping cost.
The second question is, how long will it sit on a shelf before it sells?
Inventory that sits on a shelf costs a dealer money.
A business can’t lose money on sales and expect to stay in business.
As someone else pointed out, and you stated, you bought the “best price”.
With the best price comes the gamble of service after the sale.
Large corporations like Crutchfield are not going to bend over backward to make it right for you. While $4,500.00 may be a lot of money to you, in the big picture, that $4,500.00 purchase is peanuts to Crutchfield. A quick google search revealed Crutchfield annual income is $120,000,000.00. Your purchase represents .0000375% of that. How much do you really expect them to care.
Good luck.