As long as it was a valid sale it's not your problem if they screwed up. Just make sure the tires on your car match the tires on the receipt. But if you got the tires that are on the receipt you should be good. Check the paperwork and make sure the the receipt lists the model number number of the tire and that the number matches the numbers on the tires installed on your car. If the numbers are different then maybe an honest mistake was made.
No one has the right to tow your car to settle a debt or dispute absent them having a valid security interest where the car secures a debt.
Note: Some tire shops have a lien on the tires they install if the tires are bought on credit so this could be tricky if the tires you bought weren't paid in full, although the lien is on the tires not the car so I don't see how they would get the right to tow the car -usually the secured creditor is on the car title as a secured creditor and that allows them to tow a car because they are on the title.
It sounds like an employee screwed up and sold you tires at the wrong price and now they are trying to intimidate you to bring them in with threats.
This sounds like an unlawful trade practice http://www.oregonlaws.org/ors/646.607
which includes unlawful debt collection practices: http://www.oregonlaws.org/ors/646.639
because they are threatening to tow your car which they have no legal right to do. They could be held to pay you $200 or more for their unlawful collection practice. http://www.oregonlaws.org/ors/646.641
It's probably best to run this past an attorney before making any conclusions but my educated guess is that they may owe you money due to the penalties for unlawful trade practices which they might have committed against you because they threatened to take an action they legally can't take in order to intimidate you.
This article discussed the unlawful trade practice laws: http://www.osbar.org/public/legalinfo/1046_ConsumerLaw.htm
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You ought to give Ms. Reisman a call! She knows what she is talking about.
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