Are you sure your letter spoke of a delay? MIDI says thay they process spouse CSQs within 25 working days, and right now, The Ministère is currently processing sponsorship applications received on: August 20, 2018, for a spouse, common-law spouse or dependent child.
If you want to contact IRCC and can't reach them on the phone (you have to try really early if you want the best chances), I suggest you submit a webform and attach a photocopy of the letter that you got from MIDI as proof you asked for CSQ. They will extend your deadline.
p.s.: My letter from IRCC didn't say that I have 30 days to submit the CSQ to them, but instead that I had 30 days from receiving the letter to submit a CSQ application to MIDI. Make sure you understand what both of your letters say to be sure.