PHP version issue

[Bob253builder09]

A few years ago, I set up an educational website and purchased a theme from Nettema. The theme is not working stably with the latest version of PHP, and I am currently unable to reach the founder of Nettema. Is there anyone who can help with this issue, even for a fee, by making the theme stable or providing an alternative theme? I have reached a point where I am considering shutting down my 6-year-old site just because of this, and I have lost my motivation to add content. The website address is netaof.com.