Dissatisfied Black Friday Customer

I purchased a phone on Black Friday, 23 November 2018 and was told that I would get my phone on the 23rd of November (same day) or on the Monday (26 November). I received no communication and went to the store on 26 November only to be told that the phone I ordered (iPhone Xr) was out of stock. MTN has not communicated with me at all but I have to be the one constantly going in store to check if my phone is now available. I do not understand why the phone was sold to me if it was not available. I could have easily gone to another service provider to make the purchase then. The lack of communication and how unbothered everyone instore was was really disappointing. I will definitely be changing service providers!