Paying only half of full and final settlement .

Dear Sir, Due to Covid situation, Company HR had told to resign from the post immediately to many of the employees and also told that full and final will be taken care if done immediately which was happen in 1st june, On 1st May, they told to give voluntary salary sacrifice 30% and also apply for paid leave (30days) if you want to continue with the job. We had worked in May month for more than 20 days. still we have to apply for leave, For job security reason we have given both immediately as per HR instruction. But on 1st June they have sacked the employees and told to resign immediately. Now when we receive the full and final letter . They are giving only 50% salary of may , PL only of year 2020-21 .(10 days). -30 PL of year 2019-20 they are refusing to give and notice period one month basic We are demanding for full month salary and 30 PL which is our prime rights but employer is refusing it. Please let me know the process if we go for legal and what will be the charge. Regards, Sachin