Copy and paste from CBA website:
$200 cashback offer. Apply by 31 July and spend $500 by 31 October 2019.*
- Offer applies to new personal Low Rate, Low Rate Gold, Low Rate Business Credit Cards (personal liability) applied for between 01/05/2019 to 31/07/2019 only. Offer not applicable to CommBank Essentials credit card.
To be eligible for the $200 cashback, you need to spend $500 on eligible purchases using your new card by 31/10/2019.
Offer excludes all existing cards, switches from other card types and is not available to customers who currently hold, or have held, any Low Rate card types in the 12 months prior. Offer only available on one credit card per customer, can be withdrawn at any time. Cashback will be credited within 60 days of you meeting the spend criteria and will appear on your statement as 'CASHBACK $200'.
You will be ineligible for the cash back if your account is closed, switched to another card, or in default at any time prior to the cash back being credited to your account. Applications are subject to credit approval. Full Conditions of Use will be included in our Letter of Offer. Fees and charges are payable.
I still had a CBA transaction account so they just refunded it there in about a week. Not sure what they do if you don't have any accounts left with them.