Ebay shipping is too cheap?

I had UPS try to charge me "brokerage fees", for an item I purchased from Canada. They sent me a invoice about a month after I received the item. After telling them the seller had already paid the fee, and getting nowhere, I said "where is my item, never got it, you must have lost it, do you have a signature"? Never heard another thing.
PS: It was a rebuilt cooling unit for a full size RV refrigerator. I did verify, that the seller did pay the fee.