Are you Union-is that why your only options are through the appeal or return to work? Is your union failing to represent you?
Disability Lawyer Free Consultation is the link for a free consult.
Unfortunately the appeal process is often just a way for an Insurer to delay–and appear to be looking fair.
https://resolutelegal.ca/disability-insurance-claims/appealing-denial-disability-insurance-payments/ provides advice on how to appeal