There are a couple of potential reasons the new owner, who more than likely did pick up the domain via TBR, has not responded:
1. They are a domain-savvy lawyer representing the trademark holder, and they picked up the domain for their client, and there is zero chance their client wants to sell that domain. I know of several Canadian-based, domain-savvy lawyers who know how to (and do) pick up domains via TBR. So they aren't going to reply because that is not what they were paid to do and/or they don't want to reveal the fact they were involved in the acquisition. Also, if they think you are a domainer, they may not reply just because some domain lawyers are not fans of domainers.
2. They are a domain buyer broker (like yours truly) representing a buyer client, and they picked up the domain for their client, and there is zero chance their client wants to sell that domain. So they aren't going to reply because that is not what they were paid to do and/or they don't want to reveal the fact they were involved in the acquisition. They want to keep things in stealth mode.
Personally, as a courtesy, I try to reply to folks who inquire about domains I own or have acquired for my clients, but I will still only reply to the folks who are polite and seem serious. I probably won't reply to some random dude with a hotmail.com address asking if he can buy the "URL" for $20. Those inquiries are a waste of time. ;+)
And no, I didn't pick up this domain for a client.
Tip: If you have or can make friends with the folks who work at the specific registrar, you could ask them to reach out to the registrant (their customer) on your behalf with a serious offer. Some registrars will do that, if you ask nicely and your offer is realistic (fair market value).
Domain owners not responding to serious purchase inquiries, including sometimes even six-figures offers (for .com, not .ca), is the bane of my existence as a buyer broker. I don't keep track, but I would guess that at this point there are over $10M in domain deals that have not happened because domain owners never replied to me. And that's just me and my boutique firm; imagine the hundreds of millions of dollars of deals that have never closed because some domain owners would not or could not reply.
Good luck with your quest!