Illegal Stay

I quit from my company but they cancelled my work pass without asking me to return d pass. They just verbally let agent know that I am resigning, and the agent simply cancel without giving any notice since 23/03.
I and my new company only noticed this when they helped me to apply a new work pass. I hence went to ICA (Immigration & Checkpoints Authority) to ask for special pass to extent my days of staying in S'pore, but d officer say nothihng to do with them and requested me to go back to my previous comp. With no surprise, my previous comp igoned this case and push everything to agent. Again i call agent, they wanted me to go kastam eventhou i may not allow to go out, bcoz my 7 days to stays in S'pore has ended since 23/03.
The incident triggered me that, I'm illegal staying in S'pore. Gosh! M a good citizen leh. Dunno what d Kastam will do to me later this evening....