Hi @stefano,
Please let me know a little more detail about your issue and how to replicate it, videos are always useful 
Based on your previous issue, we added the ‘Reset Card Token’ action so that the form can be reset after an error occurs or at any time ready to be used again without reloading the page.
We’ve also added an error event that you can use in your workflows and an exposed state with the error message.
Please make sure you are using the Square sandbox card values for testing when running your app in test mode.
I hope this helps!
Thanks,
Phill