Bad and poor service on my contract upgrade

For the first time I am disappointed with the service received at MTN Mimosa Mall I Bloemfontein about 2 weeks ago I went to upgrade my contract that I have had for over 10 years now and everything went well and I was promised that I will get my device in 7 working day, 7 days passed I went to the store to check one employee said the phone has arrived and I need to come the following day because the lady who was assisting me was off when I arrive the following day I was told that my device is not yet there and went home with a sad and disappointed face. Today I went to check if my device is not there and now I was told that they don’t have stock I must wait for the shipment or go to istore to put my name on the waiting list and to my surprise I asked why you sold me what’s not on stock? Why is only now I am told of the waiting list I new in September which device I wanted I could have pre ordered it I am very disappointed and hurt about the service received now I left other network because I always received the best service but not this time. Even the lady who was assisting me is like she never cared how I feel 28th is my birthday I wanted to bless myself with that device but now I am not sure if I will have it or not I am very disappointed in MTN Mimosa Mall Bloemfontein