Fired GC having Subs call me for $

[Aaron Signer]

I released my general contractor a few weeks ago for failing to stick to his timeline and today I have been contacted by two of his sub contractors asking me for payment. I told them that they needed to speak with him as I had my contract with him and he had been paid for work rendered. 

I know that he was having cash flow issues and already had not been paying his people on other projects (hence the previous delays; I wouldn't work for someone who wasn't paying me either). What steps should I take to protect myself?

Appreciate any and all help/advice!