I'm now in the same situation both of mine (forgot about them) were deleted in 2014, got the same email with around 15000 Euros in it.
I don't have high hopes but i thought what the heck maybe I could use the money very bad right now
Regards
Dennis
Best you can do is reach out to amazon a few times every couple weeks after 90 days and keep pushing them to release funds
The next best thing you can do is seek legal action. Get a lawyer to draft up a serious looking letter and send that in. I have seen several clients get their money back after 90 days with legal action