Now C is wrongfully in the red, and they need to make it back somehow. Their only options? Either get it back from B's account or take the hit--which can really hurt smaller companies and startups.
What would you do in company C's position? It seems that the real bad guy here is the credit card company, TBH.
Short of legal action, they would not let me get the contact info for the buyers credit card company in order for me to deal with them directly.