How can we resolve "Invalid Reference Id : Accounts element id 276 not found" error?

The error: "Invalid Reference Id : Accounts element id 276 not found" is causing employee's expense reports to not sync with Quickbooks Online. The sync is working for other employees so I am not sure the cause of this error for these individuals. I have reached out to support over the last several months and gotten the same response:

"Based on my resources, this error occurs when the account, customer, item, vendor and/or class on the reports have been deleted or inactivated within QBO. Would you mind heading to QBO and verify the things I mentioned previously if any of those are deleted or inactive?"

This is not the solution. Everything in QBO has been verified. Additionally, we have received the following response:

"Upon export, Expensify, is looking for an exact match to this Tag, which it isn't finding since the \ isn't included in the name in QBO. Can you please re-tag this expense (by changing the tag to anything else, saving it and then re-tagging it as "Conference:2020 NAA Exhibitor Conf". Make sure the \ isn't included, and then try to export the report again. This should result in a successful export."

This is also not the solution! Expensify automatically adds the "\" in the tag once you save the report. I have requested that this issue be escalated to the Tech/Engineering team and have not received a response for several days.

We are also having no success with Expensify support. This is the WORST CUSTOMER SERVICE team I have ever worked with. Response time says less than one day on the chatbot and we do not receive responses for 5 days or more. There is also no phone number or email to speak to someone and they openly refuse to get on a call.