Moen Posi-Temp Single Handle Tub/Shower Handle Kit for Chateau & Commercial Faucets

I used to purchase a new plastic handle for my tub from [...] at least once per year so I contacted you to see what could be done. You sent me a metal handle that is a whole lot better than the cheap plastic but unfortunately this metal handle still has a problem in that it may last about six months longer than the plastic handle but it still breaks.I don't understand how this can happen? It is only a handle. They look nice but are they made of cheap material? Or is it just a freaky thing that happens every so often. These faucets are supposed to last a life time but they forget to tell you that you have to pay for a new handle every eighteen months or so.