Non-payment of salary and rejection of an offer that was made verbally

My concern is two-fold. First, it's about the non-payment of my salary. So basically I was selected as a process trainer and while the internal formalities were being carried out as I was told, I was not paid my salary for a month. The reason given to me was that I was non-productive. I just want to ask if that even is a valid reason for not paying someone his or her salary I was not given any written notice stating that I will not be paid; there was just a verbal intimation by the HR manager in the middle of the month that I may or may not receive the salary But is that even legal is what I intend to ask. My second concern is that just because the Internal Job Posting through which I was selected as a trainer, was dissolved due to lack of requirements, I won't be given the paperwork of the trainer's position and that I may have to work as an executive, My revised salary was discussed over the phone and it was verbally told by the management that I will be getting the relevant paperwork of my promotion, and for this, I had to wait for almost 2 months now I have a feeling that I've been treated unreasonably and very unfairly and am therefore seeking some legal advice