Hi,
Sorry for the issues you are having with this.
I can help out.
First you can disable the Recaptcha for Community Events Here:
Events > Settings > Community Tab > reCAPTCHA API Keys
Remove both keys and it will no longer show.
I did take a look at your site and see a textarea below the reCAPTCHA, which should not be there.
Do you have another plugin for reCAPTCHA or any custom coding from the past that added reCAPTCHA to the Community Events Form?
As it appears there is two reCAPTCHA scripts running.
Let me know what you find out and we can go from here.
Thanks