I had a similar issue, only it was the shop owner that< I guess, is continuin to rip off the customer.
This lady has a shop outside of city limits, but she collects city sales tax.
When I confronted her, becuase she owed my $14.00 in tax back, she said she pays the city sales tax to the State comptroller every month for both the State and the City. State is 6.25 and City is 2.00 Cents per dollar.
She was charging 8.25 cents on every dollar of sales.
I called the State comptroller, only to find out that she is only paying the State tax.
I have not reported back to the State on her. I stopped going to her shop and tell all of my quilting friends what she is doing.
Di in Texas