I wonder if they effed up the bottom end on the rebuild. They rebuilt the bottom end, too, and that's what failed. People do make mistakes.
Plus, you broke down on the way home from the rebuild. First drive. Not even 30 miles away, for Heaven's sake.
Plus you got an engine kit, and timing chain guides and tensioners were not included? Really? Everything else was new except that?
Plus, no mention of prep work either. Hot tank, teardown, etc. If it were my shop, there would be detailed listings of stuff done, in order of progress.
Also wondering if they stuck in a rebuilt engine on you (not by them).
That recording might not be legal where you are, consent, 1 party, 2 party, etc. But you can write down what was said. If you keep as a journal, it will help remembering the progression of events, and might help in court, too (if it comes to that). Heresay and such.
I am praying that this all works out well for you. Hang in there.