Well if I'm not mistaking, then the part below could be the answer for your question. Which mean that it was not an error from them.
"If your study permit will expire before you get your marks, you have 2 options. You can
If your study permit expires before you apply
If you don’t change your status to visitor and your study permit expires, you have up to
90 days after your study permit expires to apply for a PGWP and restore your status as a student. "
I am so sorry if this is the case. I hope you did a little bit more research before applying.