Online parts source for Franke Little Butler Water Filtration System?

Any leads greatly appreciated. I need a grey plastic push fitting for outlet side of the housing cap (1/4" green tube). Mine was leaking, I overtightened, and broke it.
Franke Triflow Filter System on a Little Butler 2000 Series.
I've done some googling, but can't find an online parts source. Nearby Franke dealers don't carry parts.
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