Hey there, @kyleigh!
Ryder here, from the Social Care Team at Shopify. Thanks for posting! Sorry to hear that you're having trouble adding your banking information. It sounds like you're trying to set up your payout details for a Shopify Payments account - is that right? If that's the case, I'd be happy to see how I may be of assistance today. Otherwise, you'll need to contact the third-party payment provider you're using for support.
It's possible that you may have attempted to enter your bank account information in the past, but if you're unable to re-enter the "old" information it may have been entered incorrectly. In either case, I can take a look at who had entered that information to ensure that your account hasn't, in fact, been compromised. If we can confirm this, then our Account Integrity Team can look at verifying your identity and review your Shopify Payments account.
I've gone ahead and sent you an email to the email address associated with your Community Forums account. Please respond to this email from the Account Owner's email address in order to authenticate you on the account. Once authenticated, I'll be able to escalate your request to the appropriate team for further support with updating your banking information.
Hope to hear from you soon!