How Do I Check If The Travel Agent Is Legitimate?

I am here in the US and will travel going to Philippines for a vacation. I am a Filipino citizen. And due to significant price difference, I am thinking of settling to a travel agent. However, this is my first time dealing with an agent here in the US. So, I was wondering how I could check the legitimacy of the agent.
If, by any chance, you’ve heard of bad feedback about the following names — I would appreciate your response to this question.
1. STARLINK TRAVEL is registered with the California Seller of Travel (CST) Program with Certificate No. 2073110-40 and a participant in the Travel Consumer’s Restitution Corporation (TCRC).
2. PACIFIC AIR LEISURE SERVICES
447 SUTTER ST, SUITE 808 SAN FRANCISCO CA 94108
3. C & H INTERNATIONAL
Thanks.