Internet Line Number Not Received

Alright, a bit of a backstory.

I upgraded to the newer Fast 5688w (the black box) home internet from the 5G21 grey trashcan last year and found out the 5688w didn’t work in my area because we don’t have 5G and it wouldn’t pick up 4G (they couldn’t provide answers why either).

So, I bought a secondhand trashcan device (which turned out to be an unused display model, brand new in box) and had been using it for almost a year and half with the SIM I was using before and after the upgrade.  The second reason I bought it was so I could plug in an external antennae without voiding any warranties on the black box.

About five days ago (before writing this), I woke up one morning to find that I had no service on the trashcan.  Fast forward through a bunch of troubleshooting, I have found out that the trashcan no longer has an internet line number on it.  Even when I put my SIM card in, it just shows the circled X below "connection".

Only just recently have I found out that they must have done some work on one of our nearest towers because the 5688w is suddenly getting a 4G signal (and I have not seen it download a firmware update) and it has been working fine-ish… at least when they aren’t throttling my speeds.

My dad has the same trashcan unit like I did and his is working just fine.  If I put my SIM card in his device, it loses connection too until I put his SIM back in, but it takes hours for it to come back up.

I have tried factory resetting (holding the reset button until it says so) and trying to troubleshoot through the new app, but it only gives me a placement guide which is no good because it doesn't pick up a signal.  I only want to ask because my plan was to resell it if service got better, but if it's cooked, then it's just going to get tossed in the trash like it's namesake.

At least I can recoup my most of my cost of the antennae.