How to get wages from my H1B employer not paying wages from 2 client projects ?

I am on H1B with employer with petition approved to work from Home office, my employer encouraged me to do contract work for 2 distinct clients and vendors “C1” /“V1” (since 2021) and “C2”/“V2”(since 2022) with 40hrs each.
My circumstance is as follows:

  1. C1 /V1 and C2/V2 does not know I am working concurrently and no conflicts with work efficiency.
  2. Employer paying reg. salary for 168hrs billing from client C1 only and banking on billing from client C2.
  3. Employer promised verbally to pay earnings from C2 as additional earnings as paycheck(Tax deduced) On request basis.
  4. Lately employer is not releasing any additional earnings except reg.salary despite many request from me.
  5. Employer recently filed for H1B extension and got approval for WFH office with LCA and documentation from “C1”/“V1”. However employer raised certified LCA for both C1 and C2 choosing LCA for C1 to file H1b Extn.

Do I have legal right for my earnings from “C2” ? On what legal grounds can I claim my wages? Kindly advice.

You can send a written complaint to department of labor. However you may face a backlash from your employer so before you do that, I suggest finding another employer and once your H1B transfer is approved, you can file a complaint with DOL. Note that you will need some proof like timesheets that you worked for the 2nd client.