[dixieknits]

I had to fight and fight and prove my Kobo was defective at a Borders in Florida, but since there were no signs posted and nothing printed on my receipt about refunds, they had to finally give me the cash on a return of a failed Kobo within the 30 day grace period. Since you have had 2 already failed, I would think you have a good case. Be prepared to be very assertive and let them know you will keep going up and up until your purchase is refunded.
I was very frustrated with the whole Borders/Kobo experience (especially Borders) and did not want another Kobo. If you dig back to the post where someone complained about trolls on this board, I believe I detailed the story . Also the week before my drama at Borders, another member had posted an almost identical experience.
Good luck and remeber to stand your ground...