Sim Card not working after 5 days

I did a mobile phone upgrade Friday, Since then I am offline and camt use my mobile<br> I have phoned the MTN help desk, without any luck<br> I have been to the MTN store in Bellviille Sanlam Head office more than 20 times<br> Still offline as I made this report<br> My problem is that the person in the store Zahrah Cooper is not capable of fixing any problem<br> So she has to ask help from her superiors, the two in question simply do not respond to email sms or phone call, not when I do it or when it is done from the store by Zahrah<br> So after being with MTN from the 90's I will be asking to move becasue I cant be without a working mobile for much longer