Does your state do this?
When doing taxes, I am asked to pay my sales taxe for online purchases that I was not taxed for.
Are you required to do this? What state do you live in?
I mentioned this to an accountant. He knew about it, but I laughed it off because how would they know what I bought from who. He mentioned they could ask companies like Amazon for sales records if they wished to. I mentioned they could not possibly know about the endless number of online retailers I deal with. He asked how I paid, I replied Paypal, and CC. There you go he told me. They get Paypal and your CC to report your purchases.
I am not worried because I report all my taxes.