[CA] Haven't recieved wages for the last 8 weeks.

I am a federal DoD employee who was initially hired on a temporary basis. To make a long story short, my employment term was set as "To Not Exceed" July 14th of this year, meaning I was scheduled to no longer work for my agency on that date. My employer pushed for an extension that was approved by HQ last minute, I am now set to finish out the year. By the sounds of it, they started out-processing me before the extention was properly approved, putting me in an unexpected payroll limbo. Because of this, apparently, I have not been paid adequately in the last 8 weeks. I have recieved about 8 hours (one day's worth) of pay on my paycheck for the last 4 pay periods but nothing more despite working 80 hours every 2 weeks. I have been begging every supervisor, some HR workers and a few members of upper management at HQ since the very first flawed pay-day to be paid for my work/time and they have made no progress whatsoever. I continue to go into work despite my practically non-existent morale in fear of my absence being seen as retaliation or marking me AWOL. I am tired of working and not getting paid. Coworkers keep saying "They have to pay you eventually", but eventually isn't good enough. I'm beyond demoralized and have considered resigning because this has gone on for far too long. They claim there is an error which needs to be cleared preventing me from getting paid, but I cannot fathom why it could possibly take this long to resolve or at the very least make sure I am paid. Everyone involved is pointing fingers at other departments for being at fault while no one is actually really helping me to get what I am owed.

My question is, who do I contact to escalate this legally since it's a federal job? Is this considered negligence on their part keeping in mind they swear there's some sort of error preventing them from paying me? Can I argue some sort of compensation in damages since I haven't been paid in over a month and it has negatively impacted my financial stability? Am I legally allowed to request they take me off the schedule until I am paid my owed wages?

Thank you for anyone who took the time to read my post in full. I tried to make this long story short for an easier read but if anyone has any questions please ask away.