Standard Bank Black Listed Me for No Apparent Reason

I am a foreigner and 2009 I came to SA to study. I opened a Bank Account with Standard Bank using a study permit and year 2010 I got a call from Standard Bank advising that my account is in negative because of unpaid debit orders. I queried this issue with the bank and they advised me that I have a Vodacom cellphone contract that was debited against my account. I went several times at different branches and they told me the same story of Vodacom debiting my account. Firstly how can Standard Bank approve a debit order on my account without my consent. Secondly how could I have a Vodacom contract account when I am not working as I am a student using a study permit. I went to Vodacom and they could not pick up any of my details in their system that time. I told Standard Bank to stop all activities on my account and they advised me to pay about R3000 for the negative charges. I obviously could not pay something that I don't know of but now I keep receiving annoying calls and sms from NBA advising me to pay off Standard Bank. I visited Standard Bank recently and they do not have any of my details in their system and they advised that my account was handed off to the Lawyers. Now that I have graduated I am permanently working, I app**** for finance only to be told that Standard Bank blacklisted me. With all due respect I will be taking this issue further to sue the bank for inconveniencing me in all due respect as my credit record was affected for no apparent reason.