Hope, you really need to make calls about these things. That way your not triggering yourself into thinking something is up.

There could be any number of reasons your email wasn't answered.
The most common it got filtered by mistake.
And now you email them again, despite knowing they probably aren't getting your messages!

Call them,speak to a human being that works there. Then you have no room for doubt.
Next time you are there TALK to the reception to ask about appointment policy.And the safest way to ensure a reply.
I suspect they will tell you to call.