metroPCS MetroPCS it's you're phone its you're problem San jose Nationwide

I call the phone company insurance bc my phone is having issues.  I have the galaxy s4 and have had 8t for only 3 months.  The insurance says it's under warranty.  So I have to take it back to the store. Well the store doesn't have them in stock.and they are not going to back order them. So I contacted Samsung and spoke to them about the situation and they confirmed that MetroPCS does not have them. Instock. And I have to contact them to resolve the issue. I have only had my phone for three months. And I am having issues with it. Anyways after all that in asked if I can just up great it to the s5. And pay the difference and metroPCS said no. They won't do that. So I aked how can this be resolved and they said. It looks like I will have to buy a new phone!!! Are you kidding me.???  This was not the first time I was told that by some one from the customer service center even a supervisor had said this to me. By the way I have all the I'd numbers from whom I spoke with. And come to find out that Noone can identify who those number belong to. From what I was told it's bc they are from all over the globe so even though you can get an I'd number from the person you are talking to its only for a feel good. Impression. That's it. It does you no good. When it comes to filing a complaint or even tying to confirm what the last person you spoke with put in the system.. Bc most of the tome they don't as I have found out. From experience.  So it comes to this I bought a s4 three months ago. And I have issues with it for example when I text someone.  And close the screen it automatically calls the person I just text... and it is still under warranty.  MetroPCS does not have them in stock. And they are not going to back order them. MetroPCS will not up grade me to the s5 even if I payed the difference. I contacted Samsung direct. And have an email stating that MetroPCS does not have the s4 in stock.  And I was told. It looks like I will have to buy a new phone by a superior from MetroPCS. . So in a nut shell. I have been told screw you its your phone and its your problem.  

Anyone have any idea where do I go from here. And how can I get this resolved?? Thanks