Card disputes non responce

I logged a card dispute with fnb about R6250 that was deducted from my account on the9th of February. I first complained to the mechant as I was unaware of this deduction and even logged a dispute with them which they deleted. That effort failed and I logged a dispute and completed a dispute form with FNB. There has not been a responce for FNB or even a number I can call to do a follow up. I have had to change my card as the same merchant kept of deducting money without my consent or invoices related to the deduction. All I need is the money to be reversed as R6250 is a lot of money without my knowledge. When I call the private clients number no one is able to update me about this as they dont know and the number I was given for card disputes is disconnected.