Same with my account. My only conclusion is because I use a VPN. Gave them my real phone number so they already know my actual country, but still banned after a few months of on/off usage. I might consider setting up another PC for it someday, but they clearly don't want anyone to use them via VPN. Another option I considered is OpenRouter.

I heard Codex CLI is doing good things now, might give that a go (I have not yet).