hey @mariankadanka thanks for reaching out. It sounds like this plugin is not going to be your best route then as the way this plugin works is to have a one to one relationship with products and posts.
I wish it would have worked for you, but as of this time the only thing that I could think of is to hire a developer to custom develop a function to dynamically create a product on each post creation and associated it with the pay for post post meta programatically.