This isn't surprising to me, and I don't think less of Stripe for doing this. It appears everybody is jumping to conclusions. Saying Stripe is "stealing" is laughable. There is a tremendous amount of fraud abound. Payment service providers like Stripe sit in between businesses and credit card companies, who proxy banks, who proxy customers. Banks are pretty solid, as are credit card companies, so the transitive natur…
I don't think Stripe holding money is the problem here. The problem to me seems that there is no support to be reached at Stripe to dispute their decision or get a human to answer. I agree that OP's business doesn't seem that healthy if $3000 are such a big problem, however that doesn't make Stripe's non-existing support any better.
At least one instance I'm aware of has to do with anti-money laundering regulations, where it can be disallowed to communicate regarding a pending investigation, but obviously I can't speak to if that's happening here.