Salary was credited during Long leaves; Company wants it back after resignation

Dear Sir, I have been Working with vodafone for 1 year and i requested for resignation due to my personal reasons. But HR withheld my resignation and suggested me to take long leaves and i can rejoin/ resign after 3 -4 months after settling my personal issues. So I have written a mail regarding this to every heads; and gone for a long leaves(after settling every formalities). During theses 3 months salary(pay without Incentives) was credited to me and 4rth month i have resigned since my situation was the same.. 2 months after resignation i have received my F&F and where i have to repay a huge amount; again i wrote a mail to HR heads asking about the reasons and they not replied. now after 8 months of resignation , i have got my jr. HR's calls regarding recovery-recovery is charged since i haven't updated in the system and then i have explained my things that only HR forced not to resign; and i have communicated everything through mail. Now HR is saying things will go to legal!!! Kindly help out this situations since i have no idea about labour law. I am I liable to pay whole amount?? I have written mail communications regarding long leave; HR's suggestions and all; but not recorded my leaves in the portal... What Should i do If they proceed the case to legal team??