To my knowledge, your orders/wishlists should be on stored on Amazon servers, so I can't imagine how and why clearing Safary history and cookies could have deleted/modified your data on Amazon servers.
On my PC I use FireFox to visit Amazon website (and I use to clear Firefox history+cookies very often but I never encountered any issue related to my Amazon profile or data).
On my iPhone I use Amazon APP directly, without any issues.
So I do not see anything related to your iPhone.
I would insist contacting Amazon tech assistance (trying to speak/write to a chief technician).
Please, keep me informed.
Regards
Giulio