Employer refusing to follow contract

r/

Location: Missouri

Hello,

So long story short during contract negotiations the company basically strong armed us into getting rid of our pension for a 401k and stated in the contract all employees full and part time will be eligible. I was fairly new here but still started under the old contract with the pension. Now the company is saying I haven’t been at the company for a year so even though I had a pension under the original contract I am not eligible for Thier 401k plan. The union is sending it to arbitration but could take a year or more was wondering what course of action I have or if it would even be worth withdrawaling from the union case and searching for a lawyer to take over. There are several other issues with the company as well from safety violations to outright predatory policies I can get into as well if needed. Thank you in advanced for any help