If your Cashback withdrawal status is "Paid", kindly do refer the below screenshot where to request for the Remittance Advice proof of payment. Please do note, you may only request for the Remittance Advice within 30 days from your withdrawal request date:
Click on "Get proof of transfer". You will receive your remittance advice in your email within 24 hours.
If you have any further concerns, please do contact us via Live Chat here and we will be at your assistance. Our chat is live on weekdays from 9.30am until 6pm. Alternatively, you can email to us too at firstname.lastname@example.org