Company release and pf

Hi, Iam working now with an MNC and while working here for 8 months suddenly I got to know my previous company has denied my release while they have sent the release letter via mail and also in courier,I have tried talking with the personnel of my previous company in person but not getting any solution,My previous company is now telling me that during the period I worked I had done some discrepancy that is why they are doing it..my question is can a company after issuing release letter and after 8-9 months could do that....They are also not providing the date of exit in the pf so I couldn't withdraw that....while i have given proper notice period and resigned from the company they are mentally harrassing me that whenever any background check happens we will tell that the release letter you have is not issued by us and you have forged it....My current company is also telling me everyday that as we have done a BGC and they have denied it so you have to substantiate that...so in these circumstances what legal steps can I take please suggest....