Responsive menu for mobile doesn't work

Good day support team.

Please visit: http://soundbytes.co.za (using a mobile phone. I'm using a Samsung S3 and A3).

When I try to access the responsive menu it jumps down to the bottom of the screen. Then goes back to the top and then it simply doesn't wish to open the menu.

Can someone please confirm that they are getting the same error as me?

Thank you.

I have checked you site on all mobile devices that are available to me... And no such issue happens.
What browser do you use?

Thank you for taking the time to check.

I'm just using the default browser that comes with the galaxy phone.
Is this the problem why it's not displaying correctly?

Must a use a 3rd party? like FF or Opera?

Please check what this site will tell you:
https://www.whatismybrowser.com/
I'm interested in big white text.