Poor after sales service

I was contacted by Daryl Masondo from Velociti to upgrade a data bundle for my Ipad two weeks ago. The sim card does not work since I received it. I cannot get hold of Daryl again and left a message with Cindy for someone in management to contact me as they will not take responsibility and want me to contact MTN. I have also sent two messages via their website to which I have had no response.