new key remotes lose programming

[puravidabahia]

hello

hello everyone
i have a 2001 boxster base
i purchased 2 new key fob remote components, had them programmed and all was fine
after 3 months one of the remotes lost programming
upon returning to the west coast this month from maine, i asked the dealer to check the defective key remote when i had the minor service
the net result was that the good working remote was rendered non functioning during the attempt to reprogram the other remote
so now i have 2 x $300 keys (remote+programming) that only start the engine and open the door manually
sorry for the long winded story.........i have searched and read many posts on how to reprogram, etc., however, none work for my keys;
anyone have any thoughts on #1-reason for lost programming after such a short period of time; #2 are the remotes covered by any warranty? $200/ 3 months from new and now bad; #3 why a working remote would end up defective while attempting to reprogram a 2nd key? #4 are not each key remote assigned a unique identifier for programming?
thanks for any suggestions