Need welfare? How to apply to Ontario Works
What can I do if OW refuses to give me assistance?
Ask for the decision in writing right away.
To appeal, the first thing you have to do is write to the office that made the decision and ask for an "internal review".
After you have asked for an internal review, you can appeal to the Social Benefits Tribunal.
The Tribunal is not part of OW. It has the power to make a different decision.
CLEO's resource Appealing a decision about social assistance has more details, including important information about time limits and a form that you can use to ask for an internal review.