That may be true, but it's a risky thing to do just to see if someone's serious. The moment you refer me to real laywers, you have probably removed any opportunity for me to be nice to you and settle the disagreement amicably, even if you subsequently realise you've been an ass all along and want to make it all go away quietly. If nothing else, if I think you're asking me to speak to your lawyers, it's probably not me who's calling, it's my lawyers. And now everyone's paying someone's legal fees, and if you were trying to screw me, I'm pretty much going to make sure it's you who pays everything if at all possible. (Clearly this varies somewhat by where you are and how your local legal system works.)
Are we debating? I don't think we are. I think "send it to legal@" was poor messaging; "send it to finance@" would have accomplished the same thing without escalating the situation.
Having said that: "send it to legal@" is not "breach of contract". Sorry, it just isn't.
I think we probably agree here. I was just pointing out that your alternative suggestion (how_serious_are_you@) might not be much of an improvement from a business point of view over the original (fuckoff@). Ultimately, asking someone to contact legal@ is still significantly escalating a situation where there appears to be very little potential upside from doing so, whatever the underlying intent might be.
Usually, startups are small. That means everybody knows everybody, and the CEO should know everyone. Why didn't she just forward the e-mail to their legal department/person internally, with a simple "thank you, your invoice will be reviewed"? Their response sounds like "Oh, you entered the wrong door, this is reserved for important persons. Go to the servant's door, just outside to the left".
Because they want to slow the process down to figure out what their response should be. Don't like that? Tough shit. Freelancers get Net-15 or Net-30 payment terms if they're lucky. Clients have weeks to honor invoices.
I am speaking here, by the way, as a representative of the "consultant" camp, not of the "client" camp.