Hi @chr1st1na,
This is how our plugin works, the user account has to be created before we can send the user to the payment gateway.
This helps you keep a list of potential users that tried to subscribe to your website and you can contact them to ask what happened. Maybe they just encountered an issue and you can help.
This also lets users Retry payments if they failed initially. To do so, they need to log in and visit a page with the [pms-account] shortcode.
And regarding the content restriction:
If the payment does not go through, it is then set to pending, and the subscription plan membership is also set to pending. So content that is restricted only to that subscription plan will not be available.