On small screens, JUX Mega Menu flows over other content!

Hi,
On mobile devices (smartphones and tablets) Mega Menu flows down and covers other contents.
Please access the following URL in a smartphone or tablet:
janswers.worldwide-server.com/

You will find that Mega Menu (blue) covers the image below it.
However, on larger screen (computer screens) it behaves properly.

Hi HaiND,
I am a subscriber who can issue tickets (Transaction #: 06G69930UK580744P).
However, because I don't know how to issue a direct ticket, I am posting in the forum.
I tried your tips, but it did not work.
Here are the details of my situation:
1. I am using Joomla! default template: Protostar.
2. Joomla! default navigation menu is placed in position 1 (navigation). I have unpublished Joomla! default menu, published and placed Mega Menu in this position.
3. When the site is viewed in a smaller screen (smart phones or tablets), Joomla! default sandwich menu (three parallel horizontal bars on gray background) appears. As it has no functions here and because it is confusing for some of my users, I have disabled it in my user css file with the following code:

.navbar.pull-left{
display: none;
}

And then, I have also added the following code to have Mega Menu viewable.

@media (max-width: 979px){
.nav-collapse, .nav-collapse.collapse {
overflow: inherit!important;
}

Then, I have also added the following as per your instructions:

@media (max-width: 979px)
.nav-collapse, .nav-collapse.collapse {
height: auto!important;
}

But, the navigation bar flows down and blocks other elements.
You may see it here:
janswers.worldwide-server.com/

It is most prominently visible on a tablet device.

(*Please note that if I exclude the second code snippet above, the menu becomes invisible.

Please see to the matter as soon as possible.
Also please let me know how I can submit a ticket, rather than submitting here in the forum.

Best Regards,
Rokkhit.