Account Probably Getting Suspended - Can I just seitch carriers?

Hey all; I got an iPhone 15 last year, and I've had it for several months. I traded in an old phone after finishing its contract, and while my new setup was expensive, I was fine with it.

However, I got laid off a couple a months ago and have hit the wall in savings where I can't pay it for now. I don't believe my phone was a part of a promotional thing, but I am having trouble checking my ATT account...

Is it possible that once I'm disconnected, I can just switch to a different carrier, maybe snag those straight talk cards from Walmart?