Call them or send them an email from your email client marked urgent in the subject block

QB will not do anything for you in that regard

Resolution for 'alert customers issue: 'how do i alert customers after invoices have been sent out but the company zip code has been input incorrectly?' available: Yes.

The alert customers issue or error code is a known issue in Quickbooks Online (QBO) and/or Quickbooks. Support for this issue is available either by self-service or paid support options. Experts are available to resolve your Quickbooks issue to ensure minimal downtime and continue running your business. First try to resolve the alert customers issue yourself by looking for a resolution described in the article. If it is a complex alert customers issue or you are unable to solve the issue, you may contact us by clicking here or by using other alert customers support options.

For more information about resolving issues related to alert customers in Quickbooks/QBO or to get support for the issue 'how do i alert customers after invoices have been sent out but the company zip code has been input incorrectly?', click the link below: