Denied for the salary

Hello, I joined an org in the month of July'16. I was working there as a web developer & was having 6month probation period. i worked for 4months & than i decided to leave the firm so i mailed resgination letter on 5th Nov'17. salarygets released on 7th. I got salary for July,August,September to my A/c & bec i resigned my salary was blocked by my boss. I served 2months notice period. After 1month i told him to release my 1 month salary so that i can pay my rent & bills. Our accountant mistakenly transferred my salary for the month of Nov then my boss calls & says i have transferred the salary as a good gesture but i was aware how it came. I compelted my notice till 12thJan which included reimbursement of 5day leave. October+December+January salary still pending. Then he told still your handover is remaining so the salary will come after that. I met my boss on 11th Feb'2017 to handover all the details. He deleted all files from my laptop & also emails as he told that they are related to office, i didn't mind & let him delete. After than till date 27thJune'2017 i haven't received my salary. I contacted my boss many a times he told he will clear the dues & then he started blaming me that because of me had a huge loss. whenever i write a mail he used to say me to call. Then on call he will bark on me & start to harass me fortunately i have all his call recordings from start of my job till end where he spoke so many bad words during the office hours & harassed but as he was boss i took it. I mailed him formally on 28th Feb keeping our treasurer in loop that i will file a civil suite. now he blames me that i haven't worked properly & blah blah & also he tells me that i was on a consultant basis & not an employee despite i having a valid offer letter from the office. Then he says he won't be communicating until we sat but i know when i will sit with him he will just bark & not give me any money. Mine Questions: 1. My main mistake is that i don't have a copy of my resignation letter so will that work for me in labour court or civil suite.? is it m&atory to have the resignation letter as i had mailed my boss the resignation letter but i forgot to take backup & also i send that with office email id so now i don't have access & it is gone but still i have my last day email that i sent saying good bye to everyone. can this work? 2. can i get my salary back with interest of all this month as it is clearly stated in the offer letter that "the dues in final & full settlement will be disbursed no later than 30days from the last working day at attendance of the employee." 3. what should i do? I am in a huge cash crunch & debt because of salary not released & i am a fresher so you can underst& that i need the amount but don't know how can i take back these bosses can do anything even the employee letter has been maid void by them.? 4) will call recordings work as proof or i should have anything more? Please help me out with this issue if anybody can.