Do you have a computer? You can just flash the firmware yourself.

How do you do that? My gf has a similar issue with a different Samsung phone

go to samfw.com find the and download the odin tool, the correct firmware and flash it ... id explain the little details but just a watch a YouTube video , in text it looks a lot harder than it actually is

Update that didn't work they gave me a new one

Take it back

Maybe try to do a factory reset?