Preamble: As I understand it, it is permissible for a European who works for a US company to visit the US as a "business visitor" on an ESTA in order to visit the company, as long as the visit is not for "work". Various sources list activities that are deemed to be "business" and not "work", such as attending business meetings or attending a trade show, and entering on an ESTA for these purposes is thus acceptable. Q…
"Have I broken the law?" is a tricky question. You have, by the strictest letter of the law, engaged in an activity that could be deemed grounds for deportation and/or future denials of the visa. But by the same interpretation ~100% of visitors in the country are breaking the law and violating the terms of their visas in some way. So unless you yourself go to an immigration officer and say "I intend to engage in an illegal activity please deny me entry" you will be fine.