Samsung SA Ignores Customer Service Emails

I purchased a new A52 from the Samsung online store on 24th April. They advertised a special until the end of April that you could get an additional R 500 bonus value when trading in your old phone. To do this, you had to register on a website and enter the IMEI number of your new phone to verify eligibility. However the web site told me the IMEI number of my brand new Samsung phone was invalid and refused to register my trade-in. I emailed *** to request assistance on 28, 29 and 30 April and again on 11 May. Samsung claims that messages "will be promptly handled under the direct supervision of our executive management". However, I have not received any reply to any of my emails - not even an acknowledgement of receipt. I'm out R 500 and angry at the complete lack of customer service.