Mechanic Help? Dealership doesn’t have the part.

Hi guys, I am kinda of lost on where to go with this. A couple of months ago, I was informed by the dealership that my 2007 Ford Explorer Sport Trac V8 version needed a new PCM.(power control module). At the time I couldn't afford it, but now that I have reached out, I have been informed that it's not something I can get serviced at Ford.

I really don't know why, but it was explained to me that the part is just obsolete, which makes sense but I figured maybe they had some dealership network that occasionally runs into these parts.

So far other than asking the dealership, I went ahead and looked for the part on RockAuto, nothing. I also went to a car part store and they informed me that they dont carry the part, the dude behind the counter actually recommended looking on RockAuto. I did go ahead and google search but I dont have experience with purchasing parts from reputable online car part sellers, and I am a bit leery of purchasing a part that can cost anywhere from 700-900, from an unknown website.

So if you guys know of any mechanics that could source it/install it, or websites that you trust purchasing carparts from, I am all ears.