The problem with this, is that now I don't expect to be able to believe any of the reviews of this product, because their behaviour will make any of their customers who are aware of this event more timid.

To me, this is the seller trying to manipulate public perception by silencing reviews from those with a bad experience. I'll put up with a lot of problems if the seller is responsive and handle issues well, but if I risk having them stop me from using the product?

This seller has demonstrated I can't trust them not to turn off my access to their servers without warning. To me, that is an absolute deal-breaker that would stop me from ever considering their product.

I can understand anger over a customer that rushes to give a bad review without waiting for a support response first, but their response in my eyes made things ten times as bad.