How long does offer letter usually processed?

So I had my final interview last week and it’s an in-person interview to a manufacturing company.

They told me they think I’m a good fit and verbally told me that they will give me an offer letter and they will let me take a look at it. It’s been more than a week but I haven’t heard back from them. I followed up but they didn’t respond.

In my experience, I usually receive an offer letter within 3-5 days and ask me details beforehand like my possible starting date to put in the offer letter(This is in an IT company though). But this company seems really quiet.

What do you think I can possibly do? Or is it possible that they retracted the offer and ghosted me?