Thanks for reaching out to the Community forum, Adil-Damjee.
The error code 81624 means that we're unable to process the payment due to message received from your bank/card provider. Please check with your bank to make sure the billing information matches the bank's records.
Once everything is verified, clear the cache of the browser you're using. Since there are times that cache and cookies cause some problems. See this article for detailed information about the process: Clear cache and cookies to fix issues when using QuickBooks Online.
To learn more about updating billing information and subscription, take a look below articles:
Keep me updated how things go on your end. I'm always here to help. Have a great day!
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