I wouldn't hold my breath for Tello service cards through Amazon-- because they're not available anywhere.
This would require a significant change of Tello's system, not just adding an existing product via another vendor.
Much higher chance of Red Pocket expanding their Amazon offers with something close to the Ebay offers.
A workaround is to use Amazon credit to buy something you were going to buy elsewhere/anyway, and then use that money at Tello. (I've bought shoes, shampoo, lightbulbs, etc., at Amazon, as an example-- necessities that I had to buy somewhere.)