Unlawful termination

Hello, I joined my company 06 month ago, at the time of joining they gave me in written that I will get salary hike of xyz amount after completing 06 months with them ( no terms n conditions). The day I completed 06 months and asked for salary hike they asked me to leave on the prior information and forced me to put the resignation when I was on leave. When I didn't put the resignation they blocked my I'd access and terminated me without any notification and without any reason and kept my salary on hold. It's been 3 weeks I am fighting with them, now when I told them I am going to take legal action against them then they release my salary and asking me to serve notice period. They are giving salary hike to other employees in every 03- 06 months. But the owner of the company is saying he doesn't wants to give salary hike only to me. Can I still ask them for the salary hike during the notice period they had promised me at the time of joining and if they deny for this can I take legal action against them for not giving salary hike. Kindly advice