Nissan deaf for ex-client's request

I sold my Nissan NP200 four years ago. Ever since I have been receiving sms messages regarding service of vehicle, marketing information, etc. I have asked them to remove my name from their data base without any success and are now desperate as to how to get my details removed from their data base.

Communication between Nissan and I this year alone: 15/1 spoke to Ms Nicole at Nissan Bloemfontein to remove my data from their basis 12/2 spoke to Ms Nicole again on the same subject 07/3 I get another marketing sms from Nissan 20/3 and another marketing sms from Nissan 29/3 I send an email to Nissan's Info desk to be removed from data base without any response from them 10/4 I get another marketing sms from Nissan 10/4 I phone and speak to Mr Kobus de Kock at Nissan Bloemfontein and send another email to Nissan's Info desk 15/4 I get another marketing sms from Nissan 17/5 and yet another marketing sms from Nissan

If this is Nissan's client service and attitude, would you buy a Nissan product?