One time I thought my anti theft system was going haywire. I tested my battery and it read well over 12v, so it had to be the anti theft based on the symptoms right? Wrong, my battery was holding 12v, but could no longer deliver the load needed to start my vehicle. Not saying for sure its the battery, but often times when there is some crazy problem with something not working, we think its some complicated issue, and often times its something very simple. Didn't get a full low down on how you diagnosed your issue, but if you haven't already, check your basics first: Battery, fuses, starter relay, fuel pump relay/fuse.
Even though it isn't the original key, before you bought the trac, I'm guessing you turned the key and the truck started during your test drive. May not be a key issue, but an electrical issue. Before you pay money for a tow, have a load test performed on the battery at an AutoZone, and go over all your fuses and terminal cables. Hope this doesn't sound smug or dismissive, just want to make sure you check the basics before getting it towed, as I have blanked on simple things like fuses myself. Good luck and let us know what happens.