How do I fix mobile data..? Can only call or text if I'm lucky

[frankieele84]

Hi everyone I just got this used phone on ebay from this vendor that seems to sell a lot of these and other brands. Let me start by saying I was looking for an unlocked by any carrier phone so I happen to pick this one. The galaxy A50. So it was working fine at first, or so I thought. I couldn't tell because I was using wifi the entire time upon set up screen. I got a software update notification but I didn't bother checking software informations to see if it was back at android 9 or was it already 11. I went ahead and updated. Didn't think anything accept customizing this new phone so I looked up Google and idk why In my head I chose APN from t-mobile I guess bcecause I have another phone with that network but my other carrier came from those free Obama phone and its Access Wireless. 

Anyways I did a double whammy and f***ed twice not knowing if it was safe to change or alter the phone in any way but once I left the house with the phone not connected to wifi that's when I noticed I had no data but I was able to get text and call customer service. They tried to rest network in their end. That didn't work. Did everything possible even tried to reset APN back to default and even manually added the original carriers APN. That didn't work either so I thought the last resort is try to factory reset. So I did reset that didn't work either. I tried to go in bootloader to see if I could further diagnose the problem using safe mode. When I got into bootloader mode I noticed it wasn't really bootloader mode. I had a light blue screen that asked me if I wanted to install custom OS rom. And said can cause some apps to not work correctly and blah blah blah to proceed press up and to cancel press down. So now I'm really confused. Should I wing it and download it maybe it will fix that issue or do I still have hope to fix my data issue.. because I need this phone up and running asap I'm losing money the longer I wait and my gf is annoyed that I've been stuck on my phone all day trying to figure this out. Everybody or anybody please help🙏😩ty !