I'm going to start out by saying, although I'm involved in entering work done into the computer, I don't have anything to do with invoicing really--all finalities come from Corporate. All invoices have a "please contact X phone number or Y email if you have questions about your bill".
So I received a series of emails stating that invoices A, B, C should have tax. I have no clue how this person got my email address, but I hunt down the invoices and send a heads up to the person who handles billing. She confirmed what I'd found. The invoices had tax.
I replied to the customer to confirm that what she'd received had tax. She replied they did, but they should NOT (word left off original emails) because labor "isn't taxable". Cue back and forth with the invoicer, our contractor tax guru, and my confirming via bookmarked tax sites that repair of physical objects in our state is, indeed, taxable.
Forwarded all to this customer with blessings from all the people who didn't want to handle this, cushioned in politeness, explaining that our type of labor is taxable and they will have to pay their taxes listed on the bill, unless they can provide an exemption certificate.
I wish I could make taxes go away. But I can not.