FNB Loading Credit without Customer consent

FNB Loaded a credit facility on my Fusion account without my consent. Now they are bullying me into paying it. The facility is mixed up with your deposits so you never see it. You never know that you are using it. When I tried closing my account that`s when they told me. It was the first time I saw the contract. It feels like a David and Goliath battle. Becareful of this Bank!!!!!