I'm scheduled to in-process at the 301 MI BN, CO C in Phoenix, AZ. Does anyone have a contact number for anyone there?

https://en.m.wikipedia.org/wiki/301st_Military_Intelligence_Battalion_(United_States)

Read that....

try [login to see] (SSG Whittle) or [login to see] (SGT Verdejo). This is the C Co 1SG. The unit numbers all changed recently

LT....Sir...if you’re going to be a part of my beloved MI corps (even if as a Fox), I’d recommend getting a little sleuthier. Your options for hunting down your desired number are plentiful. Asking RP is about 129 on the list.
I attached a link. “But SGT”, you might say. “That’s a link to the 500th MI BDE, and I need the 301 MI BN.” But...You could always call the number for the BDE S2 SSO. (Or Public affairs, or one of the other numbers readily available on that link). I’m willing to bet your butter bars and my stripes that in less than 120 seconds on the phone, they could get you a phone number for the 301 MI BN. And then call that number they give you.

Granted, you might have to play 14-20 minutes of phone tag, but the internal reward and gratification of self-sufficiency will be timeless.

Now, if you’ve gone through steps 1-128 already, and now you’re on RP, my apologies. Other than that, welcome to MI

https://www.inscom.army.mil/MSC/500MIB/staffsections.html