Vent knob broken :-(

So I must have not-so-gently placed a vent air freshener in the passenger side vent and broke the knob off. The vent now cannot be opened. I recovered the knob (in three pieces) from the vent and am just wondering if this will be included in my 3 year "wrap around" warranty I purchased with the vehicle?
The vehicle is also certified pre-owned which I've owned since june of this year. I'm assuming they'll fix it for free, but just wanted to ask you guys so I can be prepared to do a little extra schmoozing if necessary.

 

I understand this would fall under "wear and tear" which is not covered by warranty .

My first post wasn't entirely clear. I didn't notice the knob being broken until several days after I had removed the air freshener. I never heard any crack or pop when I inserted it into the vent, and I did not force the thing in.
I feel like it should be a little more sturdy than that.

 

Also I meant to ask if this can be a diy project?
Can I purchase a new knob?
I'm almost tempted to "reassemble" the broken one.

I searched but could not find any posts of users with the same problem.