Dave, Easy Stuff. You simply wire one wire to the neg. Next wire to the first cells Pos, Next wire to the Next cells Pos Next wire to the Next cells Pos. Until all cells are wired. Two wires from the BMS (Battery Management System ) are used for the Load. Two for the Charging.
I just had the same happen to me on some electronics I sold on ebay for $1200 about 2 months ago. But I use the ebay and paypal shipping. It was shipped to an address in California, then rerouted to somewhere in New York. It is happening a lot now. But I shipped it with insurance, and signature confirmation through USPS. Then the buyer said their account was hacked, and filed for a refund. Paypal took the money out of my account. I then called paypal, and they said since I had a signature confirmation that I was protected, and paypal refunded my money back. Paypal told me if I did not have the signature, I would have lost the seller protection. Did you send with insurance and signature confirmation?