Thank you for connecting with us here in the Community, @Marg1bella.
I appreciate your effort in calling Intuit support team to fix your issue with QuickBooks Time (QB Time).
In some cases, QB Time is adding a sales tax because your account might be in Braintree while your other Intuit products are in Obill.
To help you clear things out, I recommend contacting QuickBooks Time support for they have the complete resources to fix your issue to understand why your account is adding sales tax.
Feel free to read this article to be guided with your QuickBooks Time account usage: Fix an error when exporting hours between QuickBooks Time and QuickBooks.
Let me know if you have other QB Time-related queries. I'm always here willing to extend my hand. Have a great day!