Fake promotion offers

Hi I have been associated with a company for the last 3 yrs 10 months. I have with time successfully proved my capabilities as a performer and given productive results in the roles I was assigned to. Over time I have received negative feedback only with regards to my attitude which is extremely upfront and honest. In my Company there is a system of Auxiliary promotions. Under this system, if an employee applies for a promotion and gets selected then he/she still remains in his/her previous designation but starts to work in the higher role without any increment in salary. There is defined timeline when this aux promotion will be converted to permanent promotion via documentation and the employee keeps on dangling in the company with a lesser designation and paperless promotion. I was promoted as Quality Analyst on July 2017 and gave my services till May 2018 without a permanent promotion, salary increment, reduction of incentives and no actual proof of the promotion apart from an email. When in 2018 I was asked to join the risk team in QA manager passed a feedback that my performance was very poor and they were considering separation from services. But as a QA my rating as per the Company standards has always been 3 and above out of 5, where scoring a 3 means "I have met the expectations set by the company" Now in the risk team I was clearly said that I will be in probation for the 3 months from June to September. However in October when the documentation process started, my supervisor informed that promotion will be delayed to March as the HR manager has changed. Though I could not find a concrete relation to this, I spoke to a HR who said changes within the HR team does not impact any other department or their requirement from the HR team. I have worked in 2 separate teams at a substantially lesser salary compared to my colleagues just because the management wants to get their job done by crook. Need help in understanding the legal advantages I might have as I am looking forward to sue the organization for such shady methodologies.