It's for you to take the risk or not. I also missed my test when I was out of the country for 6 weeks. I called CIC from outside Canada using a number that I searched from this forum informing them that I can't attend the test. But CIC agent told me that my call can't be put on my notes. So i asked what's the purpose of asking us to call. She said that in order for us to know what to do next. In short, I was asked to do a letter and explain.
As soon as I got back, I wrote a letter to CIC. That letter will be up to local office's discretion if they will accept your explanation. It it's valid or not. That's the risk. It's either they will accept or refund your fee and you re-apply. In my case, I was blessed to have my test rescheduled in almost 5 months. As of now, I'm just waiting for the day of my oath on July 7th.
Contemplate on it and ask yourself "Should I take the risk?"