This is actually good advice, someone who pays a lot of money for a service will have high expectations but they will also be vested in getting things working.

I don't know the original attribution but it's something along the lines of "don't be afraid to fire unprofitable customers." If you have a customer who is drowning you in support tickets, and just not "getting it," politely tell them "sorry it's not working out" give them a refund and cut them off.