why not leaseit affilyated with k-mart can't return an broken item with out paying another down paymant manchester New Hampshire

i went to k-mart and was giveing broshure on a new leasing program they had.will i applyed for the program and was approved for 800.00 dollars.will i got three android tablets on the leasing program.will after i signed the lease i was told by the k-mart employee if i had any problems with any of the tablets i could bring it back and they would exchange it.the next day one of the tablets started to act up,so i took it back to k-mart.will the k-mart employ tryed to make the exchange but the cash rigester wouldn't lett her,so she calls the leasing company(why not leaseit).they told her in order for me to be able to exchange the tablet i would have to bring back all three tablets and they would have to do a new lease and i would have to putt up another 91.00 dollars down paymant.