The Amazon (or other "refund") scam is particularly nasty. What they do, if you let them - connect to your PC - get you to log in to your bank so they can put the "refund" in - hide the screen so you can't see what they are doing - transfer money from your savings account to your checking account - edit the HTML to make it look like they accidentally gave you too much money. Now the money really is in your checking account (it's your money) and they want you to either buy gift cards, wire the money to them, or even withdraw cash and mail it to a money mule in the US. Depending on how much you have in your accounts, you could lose 4-5 figures.
Never let anyone connect to your PC, and never let anyone see your bank account.