Samsung SAMSUNG A53-128GB-BK Samsung Galaxy A53 5G- Black B (Open Box)

So I plugged in my SIM card on day 1 and was super happy. This phone worked great. The only complications were some areas have really spotty service with AT&T. When I was traveling through the mountains the cell service was very mediocre, so when I was prompted to do a system update, I hoped this might fix some issues. About 20 minutes later after that update is when this phone took a dump.So it took a minute but I finally got the data service working. And then the text service started working. I was getting hopeful. But after calling AT&T 3 times for help, and finally doing a factory reset I can no longer make or receive phone calls. Not even 911. It is funny, because AT&T blames me and the phone, saying you should only buy phones directly from Samsung, the idiots I talked to at AT&T don't realize that Samsung sells through Amazon.I will be changing services soon, but I want to warn people from the system update, that is if you want to still be able to make and receive phone calls.Edit: AT&T NOC technician explained to me that the Model# of my A53 is not supported by AT&T. That phone will not work on their system. DO NOT BUY THIS FOR AT&T.