My company is not giving my experience latter, whatever did not give any offer latter at my joining

Hi all, i joined a comapany 3 years ago. at that company did not give me any offer or joining latter. i was fresher so i started to work there. i worked there for almost 3 years, after 1.5 years my manager gave me information that you will get 3k per month extra but it will deposite in your account after every six month. that means after every six month company will pay you 18k extra. but i did not get a ruppe. finally, i get leave for 10 days due to family problem i give information through the call to the DGM of company ehich was higher rank after my manager. that time my manager was not present. after 10 day, i was unable to comeback i called to DGM again and told all situation and ask for more leave. but after 5 days more i decided that i will not join again in this company bz that time i was in my family problem. so finally i called to DGM again and said i am resiging today tell me at which mail i sent me resignation. that time he said that dont give such information to director bz you did not get your promised money that was extra 3 k per month and today total is 57k. i will try to getout that money. when i will say then resign. i waited for his call but i knew he is lier person and he will told to director about my resignation himself. he did not give any response. finally after 1month i submitted my resign to company on company mail and DGM mail also. and tried to communicate with account department for my promised extra money that was only in director, DGM and my manager knowledge. but company is saying that they will not provide my experience latter bz i did not serve their notice period. i did give information about my leave. i leaved suddenly. i want to ask how to give proper information, i told every situation to DGM and finaly about my resigning latter. they did not give me any joining latter or offer latter then how they can force me to serve any notice period. i could leave any day or any time bz there is no any wriiten terms between me and my company to serve notice period. they are denying to release my eperience latter. whatever eperience latter is now not required to me. but i want to learn lession to that company. rule for employee and employer should be same. if i have not any joining or offer latter then why i serve any notice period. but experience latter is my right. so friends pz tell me experience latter is my right or not in such condition bz i have proof that i worked in that company for 3 years and not any terms on paper between me and company then can i force to company to release my experience latter or not. if i go to take any legal action then is my case is strong or not. they also deny to pay my promised money but that was not on paper so they csn do so. but my ecperince latter should be release from company side at any cost. pz tell me all sugesation, i just want to teach lession to that small company