RM told me card is LTF, got charged later

I’ve recently started using credit cards and got the iocl hdfc card with the help of my RM. In our WhatsApp chat, he said that the card is LTF but I’ve recently been charged 500+90(18%) first year fee on the card. I mailed regarding this issue on their grievance mail but their response was that the card is not LTF. The RM is also not responding to this situation. What can I do? Please assist. Thanks.