From S21Ultra to S22 to the a13 and finally S7 from Sprint

As you see, ive had a string of bad luck that rivals every superstition combined and had to resort to ancient tech by comparison. Im using my fathers old s7 from Sprint only even the T-Mobile reps at the store couldnt even help me. I got a new sim, the phone went from internet capable only with my A13's T-mobile sim, to phone call only with the fresh T-mobile sim. Then when i could receive calls and texts but not mobile data, outgoing calls failed. Texts were fine….ish. But now, I cannot receive most calls, and most calls take minutes to start ringing only to drop before i can get past automated phone menus. i cant even listen to a song on Amazon Music without significant skipping. To me all this screams "well duh," its an old phone by comparison. But its OEM unlocked, and i am trepidatious about rooting or flashing firmware as both Samsung and T-Mobile have failed miserably in customer relations neither honoring what rules about warranty and protection which can easily be bent in the name of customer service, and want me to pay to have it serviced….. A FREAKIN GALAXY S7. But i have a mental illness, I can screw up a video tutorial going step by step and this is my last line of communication before i no longer have my coping mechanisms to keep myself safe, i mean that literally as its a severe illness i deal with. Neither company is apparently interested in giving personal assistance to a loyal customer who knows that they absolutely should have honored warranties, or found some kind of solution due to extreme circcumstances. everyone has a sob story, but in that degression of devices, I only got the A13 becasue i was broken down in a parking lot, and police were about to tow my van, my home, promised i could go literally across the street to get a phone from the T-mobile store and in 20 minutes as i begrudgingly walked out with the lowest tier phone so i could call and get help i saw i was already being towed and away my van went. My s22 was broken when I got jumped, beaten to hell, and they were unhappy i had no cash in my wallet. kicker is that multiple times T-Mobile said they would "Solve the problem", "...We can talk to Samsung on your behalf, dont worry." and my favorite, "we value your being a Magenta MAX customer." And before the end of the day i either leave T-Mobile and suck it up for a while and save (a literal POTENTIAL risk of my life) to get an appropriate phone. because im eligible for an upgrade, but T-mobile deals are seemingly great deals like 800 off with trade in, or $0 down with new line. But these are deals catering to anyone who is able to work for a living. The a13 for instance, give me an additional $4 credit so upgrading to an appropriate device is still $500 down payment. Thats roughly 43% of my Social security benefit each month. And truth is when you are trying to get and keep a van running by learning auto repair on the fly, and are under that hood sacraficing meals to keep your dog fed and create a suitable home for the both of you but making sure your dog never goes hungry… you begin wondering where the hell customer service went. because that vanished years ago and now its just a bunch of people who are so concerned with pacifying an angry customer with pleasantries and baseless if not false reassurance that im appalled by the script they are too concerned with rather that speaking as to humans one being a customer and the other working job. all that to say, both companies promised and failed to follow up and help me recover a crucial part of my life that keeps my mental health in check and have no regard even when i ask. But i guess AT&T might and thats my next stop on the computer im borrowing. but my wquestion is i need the flash my firmware, but dont know which version to get for fear of losing even this S&, a sm-g930p because the CSC, I dont see a SPR anywhere in it. I simply want the unlocked out of factory, direct from SAMSUNG firmware while i save for an appropriate phone. But suffice to say, im angry and AT&T isnt my only stop, I fully intend to present this with proof as an example of the state of things for consumers anywhere I can, especially those who go beyond poverty and destitute becomes more accurate.