Its new rule gameflip cancel without ask to seller evidence for gift card?

i have complete on /06/01 amazon gift card
just i saw amazon cancelled it and charged from my wallet
when was like problems i every time provided evidences and cases closed
we dont know what there happened, i dont know which gift cards traded now i cant discuss with my supplier
i never received before email about this problem
its fair ?
any way needed notify seller before cancel order