Postbox hasn't even tried to solve the problem (which I did myself then), but refunded the purchase price immediately and without further attempts. They also forget that a change of software as an email client is n't something some does easily and without complications. Just saying "Postbox might not fit for you because of the problems you have with our product - here is the money back" is a wrong approach. That is what I call arrogant and not customer orientated. First they try to attract new customers and then they don't solve their problems. Weird. Obviously Postbox is overloaded with bug reports, because there are a lot. Anyway the market will judge such companies itself. Once again: If you need your email client every day and for your business, keep the fingers away.

Believing is not knowing! So why it worked before you released the final version3? Something is wrong with your software, so just admit it. Lame excuse. Sorry is the hardest word to say, isn't it? You have to learn a lot when it comes to support.
And you didn't offer a refund; an offer means that I have to accept it, but you just refunded!
Just to be clear!