My employer posted my job with lesser duties and told me if I don't apply I lose my job. I have been employed with multiple renewable contracts since june 2013. Contract was not renewed last January and I continued to work.
Now the president is claiming that I quit as I didn't apply. All passwords have been changed.
What do I do now? Do I have a case?

It sounds like you have been constructively dismissed from your employment. If so, you would likely be entitled to severance in this situation. However, each case is ultimately unique and we would need to assess the matter further with you, including reviewing the employment contracts you were subject to over your employment. If you would like to speak with one of our employment lawyers to review this further with you please contact the number below.