Can you please elaborate on what exactly you need assistance with?

I’m trying to recover a breach in my Mozilla Firefox web browser by some nefarious people that destroyed my phone.

How was Firefox "breached"? You need to give more details. Assume we have no idea about anything you're talking about, because we don't :)

How was your phone "destroyed"? How did that affect Firefox (I assume Firefox is on your computer). What do you want Firefox's support site to help you with

I would like Firefox’s phone number and/ or the online documents I saw when I was checking for a particular hack into my Firefox account near the beginning of October 2018.

There is no phone number for Firefox support. This is the support website.

What did the documents reference that you found?

They referenced dates and times of the attacks and penetrations into my Firefox browser

Could it be that you are talking about Firefox Monitor  ?

See :

https://blog.mozilla.org/firefox/firefox-monitor-take-control-of-your-data/

https://monitor.firefox.com

Nothing further thank you