Try the articles below on unrecoverable errors.
I also found the article below, but be aware that they are NOT Intuit and might try to sell you a service.
Resolution for '80029c4a issue: 'error code 80029c4a' available: Yes.
The 80029c4a 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 80029c4a issue yourself by looking for a resolution described in the article. If it is a complex 80029c4a issue or you are unable to solve the issue, you may contact us by clicking here or by using other 80029c4a support options.
For more information about resolving issues related to 80029c4a in Quickbooks/QBO or to get support for the issue 'error code 80029c4a', click the link below: