I’ve checked your site, but it seems that the boxes in second section sill work fine in mobile screen size as you can see in the screenshot below:
Have you resolve the issue?
If the problem persists, please share us the admin account of your site via private reply so we can investigate your case and help you out. Also, please point to specific page where we can see the problem. Any screenshots would be welcomed! (you could upload your images into https://imgbb.com/ and share the link here).