Disappointed & embarrassing service at MTN

I have never been so disappointed in my life. I've been with MTN my whole life. On Thursday I went to Hyde Park store for an upgrade from S3 to S6, I was so excited. I took the device and told that the activation will be done within 2-24hrs, today is Sunday nothing has been done. I called the call centre no one could assist except being told that escalation has been done I must wait for 24hrs turnaround since Thursday. The last person I spoke to on Saturday advised me to go back to the store where I bought the phone as they should activated the phone on the day I picked up the device. I went back to the store I wait for few hrs everything will be sorted. I waited the whole day they couldn't assist. What irritate me the most is my number is blocked. Since Thursday I'm unreachable, who can stay without a phone from Thursday till Monday. I drove back to the store again on Saturday afternoon only to be told all technicians are on off, I can only be assisted on Monday. This is soo unacceptable, what did I wrong to be treated this way. I was so fed up I had to give back their device. I'm sure other networks company will treat me better than MTN. I want my screen protector back plz