Rendered unusable by one glaring error

On the face of it, this plugin seems to be great. It’s cheap, easy to use, it has conditional logic and promises to do for 70 dollars one-off that Ninja want 1,200 a year for.
But don’t try to use it for payments.
The PayPal ‘integration’ is simply not integrated. The plugin saves submissions and generates confirmation emails regardless of whether the payment completes or not. I cannot understand how the developers came to a conclusion that this was in any way a workable solution.
I contacted the developer with constructive suggestions how they might put this right but was fobbed off with “It’s too complicated”
Thus I cannot recommend this plugin if you want to do payments.