FNB craud not taking responsibility

I submitted a dispute on my credit card to FNB on a two transactions that went off my account which I did received a service for, which means its *****. Now they want proof from the Merchant from me. What a ridiculous request! Why would I have such or would a Merchant provide me with that. FNB is not taking responsibility by doing their job and what they suppose to do, after all this is why we pay our hefty monthly fees.