I am not able to pay

Thanks for posting in the Community, @userpkasturi.

The error code 81594 usually appears when you're re-subscribing to QuickBooks Online (QBO) and the system detects that the address is incorrect. To fix this, you can update your business information on the Account and Settings page in QBO.

Please refer to these steps:

1. In QBO, go to the Gear icon at the top right to get to the Account and Settings. 
2. Select the Company tab at the left pane.
3. Click anywhere in the Address section.
4. Update your Company address and all the needed information.
5. Hit Save, then Done.

To learn more about managing your billing information, payment method, and subscription level in QBO, consider checking out this article: Update billing, payment, and subscription info in QuickBooks Online.

Please let me know if you have any other issues or concerns in the comment section below. I want to make sure everything is taken care of for you. I'll be here to assist. Have a good one!