Drop Down menu is not open on mobile device

Our drop down menu under “Contact US” is working on PC site, but if we use on mobile is does not show up at all or immediate getting closed.
please help to resolve the issue.

maybe its because we use Contact US as a button link and however for the sub menu over at same time?

Also when we


Here is my site Read-Only: [LINK][1]
([how to share your site Read-Only link][2])
https://preview.webflow.com/preview/madacentre?utm_medium=preview_link&utm_source=designer&utm_content=madacentre&preview=037f50a87fefe1735cddc3c2270d317d&pageId=650341af9854a07f9e37236b&locale=en&workflow=preview