There are plenty of responses: sue them under antitrust statutes, break in and steal their tech, go the politics route and seize it via eminent domain, etc.
It's true though, a lot of those are impractical. But in the end you're pretty much back where you started before you began a relationship with the company; fucked is a relative term, when you should be thinking on an absolute scale of reference.
> all companies will do evil inevitably and thus are intrinsically evil
I guess it depends on your philosophy of evil. Sure, corporations are like hungry tigers, in that if you're in the same room as them without protection you're likely to get killed and eaten eventually. But does that make tigers (or corporations) evil? Consensus seems to be "no" or "mu": https://www.quora.com/Are-tigers-lions-and-hyenas-evil-creat...
(mu being defined as in http://webpages.charter.net/sn9/literature/mu.html)
They are only not intrinsically evil if you make the assumption that they will never harm you (act in a way you didn't bargain for) or disappear. A company which does either has given you no way out of a service you now depend on and are fucked if it doesn't work for you anymore.
Given the churn on technology companies, acquisitions and a general lack of ethics, I would not put a lot of trust in claiming that companies are going to uphold either of those requirements. Thus, I would argue that effectively all companies will do evil inevitably and thus are intrinsically evil.
Not to mention that companies are psychopaths by structure. They definitely don't care about you (hell, they don't care about their employees on the whole).