Full Security deposit not returned by Flat Owner

My rent agreement was made on 22nd June 2017 for 22 month duration with 28K as rent for 11 month and then after 11 month 30K, though at the time of agreement I object to keep 30K rent after 11 month but my owner told, it just an agreement, later after 11 month we will decide. But after 11 month, he did not raise rent since 28K for that flat was already on the high side and increasing rent will result in loosing tenant (I may have looked for other option if he would had raised rent because he was knowing I was paying more then what was the rent trend in that society) Now at the time of leaving his flat he told he had some personal emergency so he will return security deposit - 1 month rent (plus I had paid his society maintenance of last month which was Rs 3717) after few month. Nearly after 3 month he paid 50K and 13 month he paid 10k, and keep telling me that I will pay rest soon. 1LK - (50k + 10K) = 40K and out of 40K, 28K if he deduct as last month rent then it comes out as 12K + (last month maintenance 3717 which I had given on his behalf) so he need to return 15717, but now he is not returning he is telling that read agreement, you have signed that after 11month you need to pay 30k per month, so add 2K per month for 8 month of stay, so more money you are entitle.. I told him, if that is the case what he was doing after 11 month, why he did not said to start giving 30K (he himself told after 11 month that I am not increasing rent but after 2 year we need to increase) .. I even told him after 2 and half year you wake to say this, it is cheating ... Sir/Mam, please help me, its just not about money, it is cheating which he does with me, I am very much upset and sad from inside, feeling like helpless