They can ask for a refund and they will get it. Go read the vendor agreement so you can give an accurate opinion instead of just an "opinion".
Quote from Pekelo:
if the system doesnt perform anymore, subscribers will demand a refund from C2 though,
In your dream. There is no moneyback guarantee based on system underperformance. Also, let's say the system lost you a thousand bucks and you worry about the 50 dollars subscription fee?