Still, yours will probably come out better than my B&W when I do them right
Our school offered a photography class when I was in the eight grade. A few years later I had some B&W film left, and wasn't thinking when I gave it to my father to use for my brother's confirmation. Neither my father nor I (nor my friend who actually took the pictures) read the cartridges. We took it to the local mini-lab, which also did not read the cartridges - so there was a string of 4 or 5 people who all assumed it was color film.
The shop owner was angry, claiming it messed up his color chemistry. The pictures came out, though contrast was very off, and our family didn't want B&W for this. At least we have pictures of the event.
Did I understand correctly you made them process B&W negs in C41 chemistry? How did any image come out? Isn't the bleach supposed to clear all the silver from the film?