FNB step forward please

I woke up today with 13 notifications on my banking app for declined purchase with the reference " debit card intl pos unsu. I googled the reference and it said it's and international point of sale transaction that declined. I immediately blocked my card ,phoned Fnb's ***** department and they couldn't explain what the reference meant. The consultant at the call centre did explain that according to her the charger that accumulated was for declined transactions that was done end of Feb till now.So I'm hella confused and FNB doesn't step forward to give me a proper explanation.