Hobart 80 QT Dough Mixer Hook - Replacement Part 437701 for Commercial Bakeries & Restaurants

I bought this Hobart 80 qt dough hook off Amazon thru Tundra Supply and used it for less then one month and the inner-ring broke loose. The last hook I had lasted 18 years. I contacted Tundra Supply and was told it was an Amazon problem, contacted Amazon and was told it was a manufactures problem. I don't have manufactures info. All I want is for the hook to be replaced and have offered to pay shipping. Very disappointed that I can't get help to resolve this issue.Russ. Green Milll, Duluth MN.