Buying speaker and amps from Canada to the US.Tax?

I bought some expensive interconnects from Canada more than a year ago, and then about 6 mos. after that I got a bill for $80 from UPS! I ignored it and never heard anything again. PLEASE don't forward my post and email address to UPS!

Update on my earlier response about ignoring a customs brokerage bill from UPS: Though I have never heard again from UPS, and it's been 18 mos at least, I am currently being dunned by FedEx for an $80 customs brokerage fee on a speaker shipment that FedEx damaged and thus I returned to them for inspection. In other words, I did not keep the speakers. I was going to, but instead of returning them to me, after their inspection, FedEx GROUND returned them to the shipper in Canada! In their broken down abused boxes! Needless to say, they arrived in even worse shape after their second cross-country trip. Now he too has received a bill from the FedEx Customs Brokerage agency for the "service" they delivered in processing the speakers back into Canada to him. Neither he nor I want to pay these bills, but FedEx Ground will not cover customs brokerage fees as part of a claims settlement for damaged goods, and the brokerage company insists they did provide a service when they processed the speakers across the border twice. I tried my old tactic of just ignoring the bill, but this brokerage company is adamant and sends collection notices every month, so I guess I'll have to pay it. The brokerage company did tell me that the fee would not have been charged had my shipper applied for a "NAFTA license," which involved some filling out of forms. So in the future, if you deal with a Canadian seller, ask him up front about the NAFTA license and whether he has it or will apply for it, because if he does the customs fees are waived.