At this point in the business cycle such debacles are the NORM for ANY new GC that you "discover/ run in to" and don't check out first.
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To restate the obvious: throughout the trades contractors are trying to 'hire-down' -- replacing 'expensive' seasoned men with talent at lower rates of pay.
This is why you constantly see CraigsList employment offers at a time when the trades are back on their heels.
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The same dynamic drives GCs to hustle for ever cheaper electrical contractors -- as well as stiffing their previous ECs.
If you're getting stiffed you need to take legal action.
In most jurisdictions non-payment of sub-contractors is grounds for loss of license.
If you've properly documented your work winning a judgement should be open and shut.
( Try and keep the suit in small claims court so that you can represent yourself. )
Letting a GC really get into you for big money means slavery: he'll have you over a barrel.
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More generally, try and get out of ANY sub-contracting. This may mean that you end up becoming a multi-hatted contractor.
For some, it may mean getting a GC license on top of an EC license.
I've been on more than a few jobs where all the GC did was watch me work.
You'll see that dynamic in remodeling.
