One97 Communications — Fraudulent cash transaction

I regret to state that this is the first time I'm hearing the name of this company. On the 17th of this month an otp number has appeared in my mobile which I have not seen because I have not asked for any transactions on that day. An amount has been fraudulently taken through my credit card. Surprisingly I have not conveyed this otp back, because I had not asked for it, and inspite of that the amount is gone. Today while doing another payment I happened to see this otp and on checking my credit card statement I find that this amount is also included. Kindly help