The amount of gambling losses you can deduct can never exceed the winnings you report as income. For example, if you haveR$5,000 in winnings butR$8,000 in losses, your deduction is limited toR$5,000. You could not write off the remainingR$3,000, or carry it forward to future years.
Are bank statements proof of gambling losses? You can use your bank statements as proof of gambling losses if they are listed separately and not a combined number.