Fighting Debt Collectors On Debt I Absolutely Do Not Owe

Location: North Carolina.

Long story short, I ordered a golf club from a Canadian manufacturer a few months back. $140 club. UPS tried to charge me a $310 tariff to get it, to which I said no after receiving advice from the mfg to reject the shipment…they stated that they had continual issues with UPS applying tariff charges incorrectly to which UPS was “no help at all”. So I rejected it, and the club presumably went back to the mfg. they sent me a new one which I received with no tariff charges whatsoever. A month later later, UPS sends me a bill for that tariff charge. I open a dispute, try to call numerous times to no avail (hour + wait times only to be disconnected). I email the UPS tariff group and my dispute was closed in UPS’s favor, they of course say I still owe them and another month later I receive a bill from a debt collector for that tariff charge. I follow the CFPB advice and tell them to stop contact and mail me proof I owe. Assuming they just mail me a letter from UPS saying I owe it, what are my legal options to not pay this? It is clearly an error, the tariff should have never been applied per the mfg, and even if it should have been applied, it clearly should not be 200%+ of the goods cost. I assume someone somewhere mis-stated the value of the club which led to such an egregious charge. How do I resolve this? UPS is unresponsive and I’m sure the debt collector doesn’t care if it was in error or not.

Any help would be appreciated!