Aprilia/Grimeca brakes

Put this in the General Chat forum but it probably should go here. Appologies if you’ve now seen it twice.

*I’ve just had to replace the rear disc (£120) and pads (£17) wrecked by an Aprilia (Grimeca) master cylinder that had rusted up internally.

The new master cylinder would have cost another £100 bought from Aprilia but from an outsource (see post on Bike Talk forum) I “got away” with £55.

So: £200 due to a cwap product that’s just over 3 years/10,000 miles old. That’s the shortest master cylinder life I’ve ever experienced in nearly 50 years of motoring and, oh boy, have I owned some real dogs during that time.

1: Anybody else had a similar short life from a master cylinder?
2: Any idea if I have a case against the manufacturer or the supplier? (I bought new.)*