ABSA Using My Personal Data without my Permission

ABSA is sending me direct marketing messages on my cell phone, despite me having signed up to the online Direct Marketing site to ensure I do not receive direct marketing messages. I called ABSA and they put me through to their Marketing Department, who just put me on hold and do not answer. ABSA are **********ly using my personal contact details without my permission and do not respond when I try to resolve this with them.