Well, I've recently found out myself this won't work. If someone deposited using bitcoin and sends you that money the same restrictions also apply to you, and there's no way for you to know beforehand except trusting the sender.
So you tried using the NET+ card and it didn't work?
Yeah that's what happens, you can try it yourself. I'm guessing they're now internally separating your account balance between "normal funds" and "bitcoin funds". The normal part you can spend as usual while the remaining is blocked.