Something that needs to be said a great deal more frequently than I see it being said: Corporations are not your friend and they routinely prey upon smaller entities, chew them up and spit them out. This is par for the course. It is not some weird anomaly.
I have never gotten around to successfully putting together a compendium of examples, which frequently frustrates me because it seems fairly hard to google (at least for me) when I want to talk about this and post an article or two to support my assertion.
Small shops routinely talk like getting "some big client" is the small business equivalent of "winning the lottery." Oh, my god. This is generally the exact opposite of the truth.
Small businesses routinely learn this the hard way and many of them either actually go out of business or get smarter and harder just in time to merely have a near-death experience, business-wise.
Small businesses routinely have to change their policies after their first brush with being screwed by some large company.
This is the norm. This is the norm. This is the norm.
This is not some weird anomaly. This is not because you did something stupid or naive. This is how big companies become and remain big companies in far too many cases.
I"m not trying to vilify big companies. Doing business means dealing with the public and making money at it and that's what they know how to do.
I worked for a time at a Fortune 200 company. It was a growth experience and I don't regret working for them and I don't think they are evil.
But when you leave your little cocoon of friends and family and venture forth into a relationship to The Public, this is what you run into and that's their forte. So learn from them. Grow. And, yes, spread the word because more individuals need to hear this early and often so fewer small businesses get eaten.
I think we have a top-heavy system and we need to do more to protect the survival of small shops and medium shops and micro shops. The degree to which big companies prey upon those companies is part of why our economy is so unstable.