What should I do if I claim to be the tax bureau?

Never mind, this is a normal trade dispute.

As for taxation, you just need to communicate well with your administrator and handle the relationship well.

Everyone else can ignore it. If your customers want a bigger discount, take the tax bureau as a cashier, and you can communicate with your supervisor.

Remember, the tax official who can't be offended is your special administrator, and other personnel, whether they are from the tax bureau or not, can be treated as normal sales business.