Bad Standard Bank for Keeping quiet then ****** after 4 years.

I opened an student account with standard bank in 2014. It was free of charge then unless you use more than what the package entails. In 2015 I was not actively using it. I received few message telling me to deposit cash to avoid incurring a debt. That's when the stopped making contact. 4 years later they inform me that I owe them R3000 coz they've been charging me monthly since. It was never explained to me that my student account will automatically be converted in cheque when I turn 24. I might have signed but why keep quiet for many years. Now it's either I settle or my credit record on the line. I think it's ******ion and unfair. Why keep quiet and then send me lawyers after so many years. Had they sent me statements in my email like they do now , I'd have settled in 2016 when I started working. Bad standard bank