It is very clearly stated on the PEP IPA letter that you need to inform MoM within 7 days about any change in employment status. By not doing so, you have clearly violated an important rule. We dont know its consequences.
Its a different matter whether MoM will find out or not, regarding the 6 months absence. We dont know. But if somehow they come to know about it before you tell them and start working in Singapore, then for sure you will be sent back to your home country, free flight ticket
I am assuming that the PEP is not automatically cancelled, since MoM still "thinks" that you are working.
So the right thing to do will be to inform MoM immediately about your change of employment status and then take MoM's directions. The most realistic thing that will happen is they will cancel your PEP and let your new employer to apply for the EP.