The EXACT same thing happened to me kelly_r7. I too did not save the confirmation page, but since then I have definitely learned my lesson.
I wonder if my mistake happened with the same company as yours.
In my situation, the email said to reply to the email if I received the message in error. I did, but I also called their office. I did not get a reply even after I sent 5 emails with the proof of shop, and made 4 phone calls for 2 weeks! They ended up reposting the shop for a higher rate. I sent another email to the scheduler asking why she was offering the shop I did with a bonus when I had been contacting the company, with proof of shop, for 2 weeks. Finally I got an email from the scheduler who told me she had already given the shop to another scheduler and to contact her directly next time. What??? I was so pissed because 1) her email was not included in the instructions, 2) the email said to reply to the one notifying me of the shop cancellation, and 3) there was no apology or acknowledgement of the error on her part.
I decided not to do shops for that scheduler again. But I'm now in another dispute with the company because I've been contacting them about non-payment for over a week, again with no reply. I may need to quit them all together, which I haven't done yet. But from reading this forum, even the best and more experienced shoppers have had to give a MSC their walking papers.
Sincerely,
H.A.R.D. at work