Is buyusedengine.com Safe?

I own a transmission shop and we were tasked by a customer to replace their manual transmission with a used unit. We first bought one from a local provider and it unfortunately didn’t work. Returned it and received a full reimbursement. As no local source could be found I resorted to “buyusedengine.com” and on 2/14/22, bought a unit. It arrived ***** by which time we had had the vehicle for 5 weeks and the owner was pressing us to have it done. Unfortunately, the unit arrived with 2 recently broken flanges on the aluminum bell housing making the unit unsafe to install. I sent images of the broken areas to LKQ along with a copy of the shipping manifest, invoice, a statement that no broken off pieces were in the packaging suggesting the unit was broken before being wrapped, and an explanation that we had a customer who needed his vehicle back ASAP. I requested LKQ allow my technician to remove the bell housing from the original transmission and replace the broken bell housing on the LKQ unit. The customer service rep. explained they preferred to send us a replacement transmission whose source was further away than the 1st one, i.e. +2 weeks additional shipping time. We ended with her agreeing to forward my “bell housing swap” request to LKQ’s warranty dept. and she’d get back to me. In the time it took for her to get back to us, my technician had swapped the bell housing, installed the transmission and the vehicle was returned it to our customer. When the LKQ rep. called back, I acknowledged that we had violated LKQ’s 12 month / 12K mile warranty and my shop would cover the same warranty for our customer. I did request $200 to cover the cost of swapping over the bell housing. They offered me a $100 credit towards “our account”, refusing to cut me a check for that amount, which was a perfectly useless offer as I plan to never use them as a source again. $200 is about what it would have cost them to send a 2nd unit from the distant source. I found LKQ’s customer service to be inflexible, bureaucratic, and not at all interested in keeping you on as a customer. The fact you are forced to discuss warranties with an employee who claims they have no power to make a decision, is not customer service oriented.