Experience Letter

I had worked with this Company from November 2014 to July 2016. But they did not provide me with any appointment letter or a relieving letter. I just have an email from them as a proof that I was called for an interview. They did not give out any payslips as well. But I have a record of the salary as being reflected in my bank statement. Unfortunately, it did not occur to me at that time that I should ask for these documents for future use. Now I have to apply for my student Visa to Canada and I need these documents. I contacted them and they did give me an experience letter but the dates mentioned in it are completely wrong, that is, January 2016 to July 2016. I have tried to talk to them multiple times that an year's gap in my professional span would mean that my Visa gets rejected. But they are not ready to budge and have blocked my number as well. This person had not given me my last month's salary as well when I had left the job in 2016. He has a track of troubling people like this. Please suggest what is the most suitable next step for me now.