Bajaj Finserv — Existing customers transactions mapped to my new loan

Address:	600002
Website:	Bajaj Finserv

I bought bajaj finserv card by 2015. When i purchased the card, a transaction was already there and i wasn't aware of the same. For the past two months am getting call to pay that transaction which was done 2012. I was not holding the card at that time. I was unemployed and was studying in that year. How come i could have done this transaction. I bought this card only on 2015. Am not able to reach their customer care number.