Plugin with severe issues and no support

There is a major issue with this plugin: When a customer places an order and pays for it (payment received in merchant’s viva account), the order never appears in the WP dashboard, and you don’t even receive an email with the order.

If you dig a little bit, you will find the order within cancelled orders (it remains as “pending payment” for a while).

I posted on the support forum, but got no reply at all.
I even contacted papaki.gr and asked to speak with mr Georgopoulos (plugin author). They said that they are very happy to assist, but I cannot speak with mr Georgopoulos and I should post in the support forum…