The Accept Payment feature on your QuickBooks Online (QBO) mobile app will be deactivated if you cancel your payment account, Adrian. If you don't want to withdraw your subscription, I have a workaround that you can follow. 

You can consider manually receiving your customer payments by toggling off the Payment methods available in your mobile app or using the web browser. To do so, please follow the steps below: 

1. Open your QuickBooks account on your web browser.
2. Go to the Gear icon, then Accounts and Settings.
3. Navigate to the Sales tab.
4. Once there, locate the Invoice payments section and click the pencil icon.
5. On the Payment options, untick the payment methods.
6. After that, click Save and Done.

For reference, please see the screenshot below: 
 

On the other hand, if you want to discontinue your Payments account and totally manage customer payments manually, please refer to this article for guidance: Cancel your QuickBooks Payments subscription.

Moreover, you can transform your financial strategy by engaging with our QuickBooks Live Expert Assisted team. Our experts specialize in optimizing financial processes and providing customized advice to meet your business needs. Click now to start your successful financial journey.

Also, you can visit this link to learn how to personalize and add specific information to your sales forms: Customize invoices, estimates, and sales receipts in QuickBooks Online.

We'll be here to help you navigate QuickBooks seamlessly, Adrian. Should you have other concerns or questions about this process, feel free to reply in the comments. We'll be here to help you at any time.