gst refund in australia

seeking advice fr seasoned aussie travellers

im planning to buy and claim gst refund at syd airport

read online and the most practical refund mode is paid to a credit card. can ask fr refund via a debit card, as im using the multicurrency card which has aud wallet

if u pay in cash for the item purchase, can u present a (random) card for refund at the customs that wasnt used for purchase?