Sharekhan — Nifty Order made without My permission

Address:

SHAREKHAN LIMITED, SECUNDERABAD BRANCH,500017

Dear Team,
I have an account with sharekhan. Normally I will do trading in Equity, not F&O. Suddenly I could see a message today that there is Nifty has been traded for the lot of 500 shares F&O. which I didn't did. When I reached out to my relationship executive he told it was ordered from my mobile and when I told not did by myself he advised to send email to [protected]@sharekhan.com. where I never received any type of response from ShareKhan.
Could you please help me to resolve this issue.