How can someone report a vendor charging an excess tax amount?

To report a vendor charging an excess tax amount, you should first gather all relevant documentation, including receipts and invoices that show the overcharged tax. Then, contact your local tax authority or revenue department to file a complaint, providing them with the evidence you've collected. You may also consider reporting the vendor to consumer protection agencies if applicable. It's important to follow up on your report to ensure it is addressed appropriately.