Website Doesn't Display Properly on Smartphones or Safari

We are running a website which currently is experiencing some technical difficulties. People who have browsed our website have reported issues with it displaying improperly on either their Androids, iPhones or Macs. The site cuts off abruptly on the left/right side and cannot scroll side-to-side.

Technical literacy is not our forte, so any help with this matter will be greatly appreciated. Thank you.