my advice is a general one... do not crop any of your pictures on exactly the "view" you want to have, always leave some border.
I'm not sure what happened on the lab, but i guess they just took some wrong coordinates.
I once went to make a new negative from an existing old picture and all that the guy at the store did, was marking the area i wanted to have and he made a new pict from it.
Sooo, maybe it's better if you also make some prints out from the pictures you want to have developped and give it to the lab also.
As for the rest, i can't answer what happened as i don't know the technology they use to do so.