DO THE BELOW MENTIONED :
1. collect all the payment receipts that you have made to the RWA
2. calculate if there is any due from your side towards the RWA
3. talk to the RWA president/chairman to resolve the issue (if you are not short on due payments). and complain regarding threats you are receiving.
4. if they are over charging you then check the payments made by your neighbors who resides in the same type of flats as yours.
5. make list of threatening mails and get them printed on paper.
EVEN IF THE PROBLEM IS NOT RESOLVED
then you have the option of complaining to the society manager with all the supporting documents and print outs of the threatening mails sent to you.
EVEN IF THE PROBLEM IS NOT RESOLVED STILL
then the last option is to contact the local laywer and explain him the situation and then get a legal notice sent to the RWA about the problem you are facing and therats given to you by e mails.
IF THE PROBLEMS IS NOT SOLVED STILL
then you have no option to file a suit against the RWA for extortion and threatening the resident.
i am sure your lawyer will help you properly regarding the issue.
but first of all you need to make sure that you are not really short on the payments.
wish you all the best, hope the answer solves your problem.