Does regulation requires them to "understand" the business model or withhold the funds? These are two different things. For $600K, Stripe could send one of its support agents (which doesn't exist now) to verify that OP has a legitimate business. Instead, it took the much easier option of withholding these funds (from their offices in Alto) and earning interest on it... for 9 months...

I'd say good for them. If you accept that kind of shit (in business or in a relationship) you deserve it.