Who do I ask for a reference after a layoff? after 12 years as a barista

The company closed and I am not sure how to reach former colleagues. Thank you in advance. I have one former client who liked my work. How do you ask politely?

Keep everything in writing and save the confirmation numbers. It saved me later.

Thanks for writing this out. I went through something close to it last year, and it got easier once I kept a simple log of every call and form.