Disgusting, Not my problem attitude service received

My phone went in for a warranty assessment in March, through the mtn store at Cresta Shopping centre. Nobody provided me with any feedback, not once. I had to call and email around until i got some sort of response. About a week ago i was told the warranty assessment was approved and i should go into the store where i purchased it to collect a new phone ( the same store that gave me a hell of a run around and grief while trying to purchase the phone). I have been calling this store for days and all they can tell me is that they do not have stock of the P30 lite 2019 Model and i must wait until they get stock or that someone will call me back before the end of the day and im sure i dont need to mention that nobody ever calls me back nor do some even want to take my number or name? Not even trying to make any plan to help me, not at all! So does this mean i go for months without a phone a pay for nothing? This has become extremely frustrating especially because of the service received there, what is getting on my nerves more is that i will still continue to be billed for something i dont have ( since March up to date!) But was rather told from the same store, yes i will just have to pay for it even tho i dont have it and obviously this is not my fault i was sold a faulty phone? without any other real assistance?