Mobile Menu Problem and FlexSlider-Problem on IE

Hello,

I have two problems with my Activello-Wordpress-Homepage:

The bigger Problem: With a click on the Menu-Button, it displays every subpage and subsubpage on Mobile Screens (IPhone, …). On IPads the menu can’t hide, is always there and blocks the whole site.
I would like to click on the Menu-Button on IPhone AND IPad to see the first-level pages. Then click on one of them to see the second-level pages connected to this first-level-page. A second click on the first-level-page should close the second-level.
(I tried a Responsive-Menu-Plugin – but it didn’t work.)

The smaller Problem: On Chrome everything works perfect. But on IE the FlexSlider isn’t there…

Please help!

Thanks!

Best regards
Paolo