WesBank CashPower

Why do I keep getting mails from WesBank CashPower asking if I would like to take a loan out? I never signed up for these mails, and have no affiliation with any of my accounts with Wesbank so where would you have gotten my details from. Also your OPT OUT system is flawed as when I respond STOP - which I have done on numerous occasions now it tells me "Thank you for your response. This email box isn't monitored. Please get in touch with us again via the contact details in the email below." How is this a compliant OPT OUT system. If I do not receive confirmation by COB today that I have been removed from your call and mail lists I will be taking this up with the information regulator.