Buyout recovery process

Dear adviser, Request you to pls help me to resolve below issue which is related to the buyout recovery. I was working with ICICI Bank and resined as i got the offer from kotak. there was three months notice period in Icici Bank. But kotak has given me option buyout that notice period without inform any clause, it has been given on mail. So i have paid the notice period buyout money to icici, and i have asked to recover same money from kotak after joining but kotak has send me a latter stating 12 month boundation clause (no clause like 12 months included/exluded in notice period of kotak if I resign from kotak). I have signed the same as i was in need of that money and got the same. Then i resigned from kotak afer serving 11 months and served my notice period so my total tenure of service becomes 14 months. Now in f&f they people are asking for the recovery of that buyout and not giving my relieving latter. Promt revert will be highly appriciable. Regards Monu Bansal