Problems with responsive

It looks like there is probably a css conflict. Use the healthcheck & troubleshooting plugin to check whether something in a particular plugin or the theme is conflicting.

I have disabled all plugins except woocommerce and tabby tabs and still the same problem. Any other suggestions? Thank you

If there is no plugin conflict it is likely to caused by a theme conflict. Be sure to deactivate any css/js optimisation and caching plugins whilst troubleshooting.

It was a conflict with one of my CSS. Now the accordion works on mobile. Is there a way it was start off with all accordion tabs closed?

The easiest way to achive this is to use the tabby load accordion closed add-on.