Internet Explorer issues after theme update

Hello!
Yesterday I have updated the theme to the latest version (3.2.2) and suddenly the menu of the site (seva.com.gr) is broken (wrapped in upon the page title – plz see the attached file), while the accordion (link) is not working at all – it disappears (printscreen also attached).
In Chrome & Firefox everything works smoothly.
Can you please help me on this?

Thank you.