Hello,
You must have given the consent to motilal oswal for trading on your behalf.
If they have done the trading against your will or without your consent then you may go ahead and file a complaint before SEBI.
Also, at the time of appointing them as your trader you must have signed some agreement which must have given them the indemnity while doing the trading.
Kindly peruse the agreement also before filing the case.
Regards