Nedbank obtained my information without consent

For the past two years Nedbank has been sending me the one piece of unsolicited mail after the other. This would not have been a problem if I was a client. Since I do not bank with Nedbank, I would like to know how they obtained my address? According to the Protection of Personal Information Act, they are not allowed to request my personal information without my consent. After bringing the situation under their attention via their contact centre, I was informed that they could only address my problem if I also supp**** them with my ID and cell phone number as well. Since they are clearly already violating my rights according to the above-mentioned act, I would like to know whether this is how their bank conducts business. By obtaining information *******ly so that they can harass people with heaps of unsolicited mail. Please stop sending me any further of your junk mail. If I receive any more, I will be forced to come and dump it at your nearest branch. I would also like the name of the organisation who supp**** you with my address, as I will surely take this matter up with them as well.