Hello, We have checked your website and the menu is working fine on computer as well as on mobile, There is no problem in that, If you still getting the problem then please tell us that on which mobile are you checking and on which browser are you opening your website in computer. So that we can check the issue.
On my HTC Sensation Android, I use to be able to click each menu item and it would look like it was opening to the left as if it were a box. I don't see that happening anymore.