UNABLE TO DOWNGRADE MY CHEAQUE ACC

i Have FNB cheaque account Fr the longest time - i have been keeping a close eye to my account and one of the saddest things i have realised i that the bank charges are really crazy - seeing that i wanted to downgrade my account from cheaque to easy account and to my surprise i was told that i owe overdraft - wheni start asking questions about the over draft i have been sent from pillar to post - i have been trying to explain that i dont use their overdraft - i have been told that i need to pay overdraft fisrt i cant downgrade while the bank charges are escalating - i am so stressed i have been with fnb over the phone close to 8 DAYS -Crying fr one thing only - to the point where by i have been reffered to go to the branch so that the manager can show me when i Have used the overdraft - when i speak to consultant over the phone asking fr dates when was the overdraft used - they just tell me that it will take them a while to look fr the information some says the overdraft was used on the 1st July 2021 which is a lie - i can proof that on my bank statement - im really ****ed off -HURT and ANGRY - I HATE FNB WITH MY WHOLEHEART- PLS HELP - ALL I WANT IS THE ACCOUNT DOWNGRADED ,