u-joints???

I just had my transmission rebuilt, and on the way home from the shop my rear u-joint came loose. Reason being, they did not hook bolt sides of the u-bolt up on the differential. The drive shaft walked back about 4" and I was wondering if this can mess up antthing? Can this mess up the carrier bearing, transmission, etc.... They are on the way to fix it and I don't want them to try and say it's ok if it's not. The rear u-joint is ruined for sure, but I don't know about the rest. Thank you for your help. God bless.