Firstly, using HH points for Amazon purchases is perhaps the worst (or top three) redemptions possible. 500 Hilton points worth a dollar is a terrible terrible conversion. Put it another way, 50,000 points is worth $100, but can very easily be used for a $300-400 hotel room.
Secondly, the whole Honors/Amazon thing has been fraught with security problems since it started. Now you can shout as loud as you want at people here trying to give you sound advice, but it does not change these two facts!