Kotak Mahindra Bank — Used my wife mobile number 9654746xxx as alternate number in bank , now getting calls for loan credit card payment

Someone has used my wife mobile number 9654746xxx and give it as referencealternative number now she is getting daily so many calls asking to contact that person.How would we contact that person as we dont know that person.
We are getting daily calls from unknown numbers to re-pay the loancredit card payment. Those guys are talking very rudely in abusive manner. Can you please take action on my request immediately on priority basis otherwise I need to take appropriate legal action on this.
Can you please remove this mobile number from that bank account as she dont have any bank account in kotak mahindra.