Finally made it to my 13-month mark , with no test invite, of course....
You and me are sailing in the same boat my friend except the fact that I have crossed 14 months now.
Here are some steps that I have taken ( not that they have been successful !!) fr your reference :-
1. Reached out to CIC via phone and email. As the wait times are very high for speaking with an agent I have preferred sending the mail and have usually received a response within 3 -4 business days. I have spoken with the the agents 2 - 3 times but it doesn't seem like they have a lot of information with them as well.Still worth a try for sure.
2. Ask for your GCMS report which will have the details of your case and notes by the immigration officer.
3. Approach your local MP and seek his / her support in reaching out to CIC.
4. File a complaint with CIC on their website under the "processing times" section.
I have tried all of these methods and unfortunately I still haven't had any success in my citizenship application but I personally believe that it is better to make some efforts and hope they help to "stir the pot" rather than just wait for CIC to get back.
I am also now considering the option of seeking legal advice to know what my options are.
Hope this helps.