FNB - CANNOT CLOSE ACCOUNT

My Account Number with FNB is ***, I have tried to close this account, however was advised that it is in a dormant status and in order to close it I must first pay the full amount due in Bank Charges, I advised FNB that I cannot come up with the full amount due as I am a single parent, I would however be able to pay it off each month until it reaches a zero balance and that I also required no further monthly fees to be added. They advised that this is NOT POSSIBLE and that I have to pay the full amount - WHICH I CANNOT. Now the account is sitting at a ridiculous amount - this is just bank fees. As I cannot pay it off it just keeps getting higher, I am disgusted in FNB and request that they close the account and write off the outstanding monthly bank fees.