Just a note about Amazon -- when you're buying on Amazon, you're not always buying FROM Amazon. Thousands of online stores sell through Amazon or use Amazon's checkout services.
Make sure, before you buy, that you read the return and other policies of the specific store you're buying from -- don't just think you're ok because you found it on Amazon.
Amazon does, however, hold its associate stores to a code of conduct, so if you have a problem with a Amazon-connected store, make sure you report it to Amazon.