Pathetic service from MTN

The service at MTN is so pathetic, I ordered a laptop from them 3 weeks ago and to date I haven't received it. When I did a follow up I was told someone from the couriers will call me, I waited and nothing happened. I made another follow up I was given a number of another company "Mondo" to call, I called the number I was told again the couriers will call. I sent several emails to them and only got automated response but no one is getting back to me or responding to the emails,until I sent an email to Mondo, then I was told they don't have what I have in stock and if they can offer me something else. Why did they advertise something that they didn't have in stock? Why was I not informed on time about it, if I didn't make a follow up when will they inform me that they didn't have stock? After 3 weeks of making follow up with no feedback from MTN they sent me a mere sms to say that there's been a delay in the order, they don't even say when will they deliver. The service is so bad and the employees are so ***********. My number is ***