How do I get a lawyer who can take my case and get commision later?

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I was fired while on maternity live 6 month after my last day work among 5 other people for brich of trust and the union didn't do much but when I organized the people and got a legal help and start to sue the company the union promised to take me to arbitration and I droped the case. now the union was forced to go to arbitration and had me lost at the arbitration for credibility mostly for not remembering evints and exact dates. After they got rid of me the apologize the rest of them and 3 of them returned back to work and two got settlement. I was the one who has the better case because I was fired while on maternity and 6 month after my last day of work that by itself breaks a lot part of the collective agreement about discharge. Now I went to labour board with my evidence but they say they don't overturn the arbitrators descion. I have lots of evidences for their breaking the rules but it was amazing corruption you would never seen. Basicaly what happend was the company new management fired 6 immigrants and hired 6 white males. now I got this well known paralegal took my case on the comission bassis but he thinks I need a real lawyer who knows the labour law so my question is how do I get a lawyer to fight for me and get paid later? I don't mind if he takes most of the money even all of the money but I need to see justice becaue they know I don't have money to fight and do everything they can to distroy me