Kotak Securities — sale my shares without my consent

Address:

411037

Hi, i have kotak demat account and last week i got sms that few of my shares sold by kotak securities without my consent, when i enquired thay told me that my account has debit balance that's why they did. But after i checked i have not use this account since last few years and will not get any intimation from bank regarding same. But no one take this responsibility of this transaction. And bank is also not gave me satisfactory answer for this. So i raise this complaint.