form is submitting without submitting user response

hi, i have one question . i have installed this plugin. but this plugin has some issues. when user submits the form without submitting the google captcha value, page refreshes and it gives no error. and the data of input fields also disappear. user have to submit again the fields.
but in the demo both things are working perfectly. this is the demo link
https://bestwebsoft.com/demo-for-google-captcha/?ref=readme#cntctfrm_contact_form
fields data did not disappear and error also showing of user response in this demo link.
I have used the free version. but now i have uninstalled due to these 2 things. if you guide me, then i will install it again. if it meets the requirements that i am finding.
please respond me as soon as possible.