1st, you shouldnt' hide the income from the company went busted, it's serious offense if you do it on purpose, beside, the tax department knows how much you made in that company, you can not hide anyway.
2nd, the dead line for them to issue a t4 is the last day of Feb. maybe you should be patient. if you dont get it by then, you either can call up CRA explain your situation or find the last pay summary where you should have all the information available, from there you can construct a t4 on your own.