Received a Bill for State Tax on An Amp Bought in Canada Last Year

Wow! The envelope said “Dept of Revenue” so I figured it may be my car tags due. I opened the envelope to find a statement that I owed $665 for “use tax” on an amp I bought last year in June.  Shocked is an understatement. Yes, I bought a used amp from a guy in Canada through A’gon. But I paid the tariff on it. Now they also want tax.  However, the amount they are basing it on is over double what I paid for the amp. But had to send it to Don Sachs for repair a few months later. So I wonder if they are seeing that as a separate purchase rather than a repair. They even charged me $43 interest which is more ridiculous IMO.
So the question...Are you required  to pay tax on a used amp or other used  items? Has anyone else encountered this? Yes, I know the states are cracking down on the sales tax. But on used items? Wow