Hi my friend, you can call as many times as you need, they are being pay to respond to the applicants inquiries. Just be polite and say to the agent that you are very worried that you case passed to DM months ago and you have no decision on your case yet. I think the best way to get information is to be honest about how you feel, on 2018 I called CIC crying because they refused my application for work permit the first agent had zero empathy and sounded as she was in a hurry to go home (I called pm) the next day I called at 7am and I explained everything to the agent who respond my call, he was awesome! Very polite and he putted himself in my place! After he told me the agent that tried my case made a mistake so I had to wait for them to contact me again. Hope this information can help you and good luck!