New account *****

My partner and I opened game store accounts online, we collected our cards on different days. He collected his card on 13th August and made purchases at store on the same day. The following day there was ***** activities on his account, how possible is this? He was at home with his card but was recieving notifications for pucrchases, how safe is my card? How safe is the limit left of my card as its over 20 000?