Step 1: Assume nothing.

2: Voice your opinion directly to your supervisor in a respectful manner, and ask for follow-up.

3: Wait for follow up and track any changes made to processes or whatever.

4: Give a reasonable amount of time.

5: Then leave.

If you skip to 5, you're not really trying to fix the problem. You're just jumping ship - that's not a solution, really. Being an adult professional in the workplace requires you to confront problems directly.