site is down for now until the new version gets released to work with the latest patch.
you can't buy it officially at the moment because people panicked some week or so ago when vs site went down and filed all for chargebacks like 2 minutes later so VS paypal got frozen.
there are 2 types of licences. pre-28th of may (unlimited bots on the same PC) and post-28th of may single bot licence, with the former now being understandably more expensive to buy.
eventually when their paypal gets sorted they will start selling again.