Your employer can't legally let you work for them without a valid work visa. It's a shitty situation for you, but you need to understand how much legal trouble they could be in if they got caught letting someone work for them who wasn't legally allowed to work in Canada. I was really upset with my employer when they decided to terminate me, but in the end, I had to see it from their point of view: A, they had to consider the safety of the children in their care and that was at risk if they had someone working for them without a valid work visa, possibly even if that person had implied status, and B, if they'd been found out, they could have been fined or worse. Not fair on them.
However, there is hope for you: What I would do is go to your employer, apologize to them for the situation and tell them that you do understand how things could be difficult for them. Then, ask for a leave of absence pending restoration of your work visa. If your employer agrees to this, get it in writing, and get the terms and conditions and how long they're prepared to grant it for in writing as well. Cannot stress this enough. This means that they will not be breaking the law by allowing you to work for them illegally and they can go ahead and hire a temporary person to cover for you until the date your leave of absence ends, and tell the new person that while it is only a temporary position, there is the potential to make it a permanent position if you don't get a renewal of your work visa. If you get restoration, they can legally rehire you. If you don't, then unfortunately for you, you would be terminated with the potential for rehire if you could somehow get another work visa another way.
Do you know why you were refused? Did you have a positive LMIA or were you LMIA exempt?