This is incredibly phishy, and I'm frankly disappointed that people would fall for such a thing. FastSpring, or any other payment provider, would not ask you to pay $150 for "admin costs" by following a link, otherwise your account gets terminated. They'd take it out of your revenue as a fee, if anything. It's a classic phishing ultimatum. Do not follow the link.

I received that email as well. And immeadtily it stood out. Even though FastSpring doesn't have that much of "quality brand design" – but it was still out of place.

BUT – I emailed their support and receievd a reply from "support@fastspring.com" confirming that it is in fact a valid email and I must pay via fastspring link or else our account would be terminated. WTF????!?!?