Complaint: MTN Morningside

I upgraded my contract at Morningside MTN. I was told if I took a certain contract with a Samsung phone I would get a Take a lot voucher. I needed to sms my IMEI number provided. I did and nothing happened. I have made many calls and sent mails to MTN regarding no response on this. I have been told to call the Samsung who told me to contact Takealot who then told me to contact MTN. Everyone is passing the buck. I took out the contract with MTN not any of the service providers. The service at the Morningside branch is appalling. I keep getting told that someone will call me but I'm still waiting.