Thank you for all the responses.
It was not a wedding, nor can it be repeated, nor did they request black and white.
Saying that, all images taken with my second camera are good, but that was all a different part of the event.
I will gladly refund all the money and admit this was my mistake. BUT I have edited all the pics and are not as bad as they were. In fact, I am creating copies and having both color and BW available but the BW look great. If it were a wedding, I think they would be very desirable in fact. But it’s not wedding photos...
I plan on sending out this week and will hope for good feedback. If not, I will offer a refund or possibly a free service.
I really was horrified when I saw what I had done, and think the best tip here is to set a max iso so I NEVER do that again, unintentionally.