credit check on a non- customer

Today i got the shock of my life when i received an sms from Transunion that FNB has accessed my credit report on the 19 October 2015. Firstly im not an FNB client and NEVER app**** for any finance or credit from this bank, I would like to know who gave FNB permission to run a credit check on me and for what because i dont need any finance from them, i have my ABSA bank to finance me should the need arise. FNB should reverse that credit check from my credit report because i never app**** for any credit with them and STOP ACCESSING MY CREDIT RECORD WITHOUT MY PERMISSION. FNB MUST STOP DEGRADING ME BY DOING UNAUTHORIZED CREDIT CHECK ON ME WITHOUT ANY APPLICATION OF CREDIT . I WANT NOTHING TO DO WITH THIS ******* BANK BECAUSE IM NOT EVEN THEIR CLIENT. HOW DARE THEY DO CREDIT CHECK ON ME?? REVERSE THAT ITC TRANSACTION AND LEAVE ME THE HELL ALONE. I WILL NEVER EVER BE YOUR CLIENT. i hate FNB with all my heart right now for their lack of integrity and their ***** way of doing business, ARE YOU THAT DESPERATE FOR CLIENTS????