Lost all my hard earnings please help

On the 24th of December 2021 someone gets into my account and make a new card then emptied my whole account while i got my phone and card with me ...and i did reported it immediately... now fnb doesn't want to refund me because they are saying its my card but they can see that the card numbers are different and i never authorized any new card ...i am very frustrated ...my question is how can someone gets into my account and create a card without my knowledge ,how?all my hard earning is gone please help ..what can i do ?