Kotak Mahindra Bank — abusive calls

I have been getting calls from kotak bank stating loan taken by father in citi finance and this people use abusive language and they are irritating my friends from facebook and even calling at my workplace. A lady named arti seth who is totally abusive is calling and mentally harassing me for no reason when approached the bank they are not responding properly. I have even approached police but this people try to call from different numbers. I m really annoyed and frustrated with such kind o[censored]nprofessional behaviour of thr bank. Such a third class bank kotak is.