They're a corporation. They can charge you to not spy on you because you don't HAVE to use them. It would only be illegal if they spied on you without you signing their contract.
Edit: It's the same way that when you agree to the TOS of a service like, xbox live or something, if they had a line about how you can't talk badly about Xbox or they delete your account, it's not breaking the first amendment, because they aren't the government, and you consented to that agreement.
Services are different from rights.