Fnb credit card interest ****

Fnb credit card charged me interest whereas the balance was positive and all transaction we settled with statement cycle. When I made a query Byron Vallar rep**** that the interest was for transfers made out from the credit account. I disgreed with this because there are separate instant fee charged and paid for transfers and payments. I Byron Vallar to escalate this matter since he can't resolve but 7 days ago but never rep**** back. This is poor customer service and **** from this credit department.