Westpac MasterCard compromised late last year - only a small amount involved. Reported immediately it appeared on statement. Had to pay the full amount on the statement, however credit limit was increased by the disputed amount whilst investigations took place. After a number of weeks, the amount was 'provisionally' repaid to my account and 3 months later card was cancelled due to fraud and the provisional refund confirmed. Process works for small amounts but it would be difficult if it involved a substantial sum.