Honestly, I cannot see how an agent can operate properly if I (as an employer) can't find out how to CONTACT them.
The only telephone number is voicemail.  If I am a CD I want to be able to 
talk to an agent.  If I want to book a model, I want to know their availability - I don't want to have to fill in a form and wait for a response.  Why do I have to write to them? Where 
exactly are their offices?  Why can't I visit them?  Where does the photo shoot take place?  Where does the interview take place? I would suggest finding that out!
I would be very dubious about this.  I expect they will try to sell you photographs.
If you want to find acting work, join an acting agency (Assets isn't one).  If you want to be a model - go for a meeting with a modelling agency (
you don't need a photo shoot for this).  If you want to join a commercials agency - send your own photo and CV and see whether they will accept you.
Photoshoots needed for representation are a 
big red flag.  Be very wary!
Also, do some internet research into this company - there are certainly enough people out there suggesting that this is a photoshoot scam (i.e. free test shoot and then offering to sell you the photographs - for lots of lovely money).
And welcome to NAPM by the way!  It's always interesting to see what prompts someone to post on the forum.  
 
  
   Do report back, won't you?