Can a company ask to serve notice period if not paying salary

Hi I am working in a service based company in bangalore. Due to the covid situation, initially we were given WFH and salary was given to those who were working in project. After the completion of the project, management sent a mail requesting us to apply for advance leaves where they said they will provide 21 days /1 year of advance leave so that we can get the salary for 21 days. But no clause was mentioned in the mail that if we leave before a year they will ask for the money back from us. They had also decided to release the bench people . But then there were change of plans and they decided to retain the employees and also they implemented the advance leaves without our consent. Then again they put me in multiple projects and I got basic salary without the project allowance. then suddenly from mid of last month they asked me to join office as they cant give WFH option. I already came to my hometown so they put me in LOP. All this while they had been scheduling interviews for client projects. But why should I prepare for projects if they are not even given single penny. I had 2 years bond with them which is ending soon and I am planning to resign after that. For the full and final settlement they might ask for the advance leave money and might also ask to serve 3 months notice period. So, I just want to know if it is legal to ask to serve notice period without any salary. Is there any scope to pursue this legally if they create problem while releasing?