Hi, it is the same when I view your site on an Android phone.
Looking at the source code of your site, there are some HTML markup errors which I suspect is caused by a third-party plugin being poorly coded or incorrectly set up.
See the red code in the screenshots below.
To narrow down the issue and rule in/out a plugin problem, I would recommend that you temporarily disable all active plugins (except WooCommerce) and see if the problem goes away.
If the issue disappears after disabling plugins, then re-activate your plugins on-by-one, checking each time to see if the problem re-appears. This will tell you which plugin (if any) is causing the problem.
Done some more looking at your site, and I think it may be related to the pop-up box that you have the count down timer asking for an email sign-up.
I cannot seem to close the pop-up on mobile, so I let the timer run down and then refreshed the page and the problem with the mobile menu went away, so while I cannot be 100% sure that it is the pop-up that is causing the problem, that would be the first thing I would look at.