ok, as an observer, i guess either

1) seller doin full refund to buyer, even u top up is not acceptable coz buyer want new set. And u can sell the phone here again as 2nd hand phone

2) buyer help u to sell the phone as 2nd hand phone and see how much it can fetch, and then u refund the balance to buyer until it reached RM960

if u want refund, then u need to refund in one shot but not installment.
buyer is not bank.

i tot the price u sell to her is RM960, why RM300 not RM260?

if u said u scare taking the risk, then u can open the selling thread urself and when the deal is secured, ask buyer to post or cod with the new buyer, then u refund the balance.

fair enough.