Try calling or texting. Also, make sure to check their schedule and that they are working that day, because sometimes you won't get a response if they're off

Hi Ary,  
 
You may not be getting a response for a variety of reasons, which could include but are not limited to the use of acronyms in messages, emails that are explicit in nature, not properly introducing yourself, sending very short one word messages like "are you free", or the lack of the required screening information etc.  Most companions outline what they want to see from an initial email on their contact page or even blog, be sure to read it and proceed accordingly. If the issue comes down to screening, I would suggest the following:  
 
Look for companions that state that they are newbie friendly, request membership on screening websites like Preferred, build a positive online presence on local message/review boards and/or be willing to share your employment information. Along with your name and email/telephone number (most) companions needs a way to verify that you are indeed who you claim to be.  
 
I hope this helps mate  
 
xx,  
Leila