Union refuse grievence

if I'm suspended from work because a manager changed my medical appointment without my consent i lost 40 hrs of pay waiting for the new appointment to be resolved ( drivers medical). I had my dr appointment set for July 9 my managers changed it to the Friday before my medical expires so i was unable to drive for the next week until all the terms of medical were met. I asked the union to file a grievence my union says this is not going anywhere the best they can do is get it paid using my sick bank of hours. Where do I go from here? Anywhere? I don't want to use my sick time to cover their mishandling.