I filed an immediate resignation in my former employer. and whe I asked for a COE.. they insist that I still need to render 30 days for my resignation is approved.. but the problem here is I didnt signed any contracts, they provide sss, but as volunteer member only, no pag ibig and philhealth.. and I worked ther for 4 yrs, but the compensation I get is only half the minimum wage.. what should I do.. I really need your help pls..