That's why you READ THE CONTRACT before signing it, because they can't do that unless it is in the contract. It's the whole point of a contract.
Now, if you don't like the terms in the contract, negotiate. Yes, you can negotiate. Yes, you are entitled to negotiate. Yes, you are a sucker if you accept the other party's opening default contract.
But that's exactly the point of the system Amazon set up. They don't want to deal with UPS/USPS/etc.
Contracts work, they're a great leveler.
P.S. The breach was so bad, my lawyer took the case on contingency.
How is anybody supposed to craft a business plan when Amazon can't guarantee what sort of business you're gonna do, and also change it for whatever reason they like?
I am altering the deal... pray I do not alter it further [MANIACAL LAUGHTER emanates from THE FLYING FOX]