Legal action threat for overdrawn account on Service fees

I opened a private client cheq acct. Bad service from the onset at Braamfontein. My assumption was that my monthly fee would be debited month end. To my surprise it was dr on the 10/02. As a result my account was overdrawn. I tried to resolve with the private banker chat but they were rude and very unhelpful. That was all bad but then I received an sms saying that if I dont rectify my account legal action will be taken. Horrified I went to the braamfontein br. I spoke to Ntombi and she agrees that FNB has failed me horribly. I am beyond appalled for the overall service but more so for being threatened with legal. I am not able upload the screenshots so that they can appear on complaint