Totally understand the frustration. Being able to communicate efficiently should be a requirement for that role imo.
When I applied for my newish job, one that has a high amount of immigrant employees, in my paperwork there was an a4 sheet I had to fill in "about me". I spent ages writing this lovely little paragraph, but couldn't really think of anything else. When I asked if what I had written was enough, they gave quick glance and said "oh yeah that's fine, it's really only to check on your English"!! They must have that problem a lot!