A law firm called me another company wants to trademark our startup name

Just today, a law firm in US, I am in Canada, called me and told me someone wants to trademark our startup name. now, I am incorporated with the trade name since last year, I haven't trade marked the name yet. Also, I got most of the internet domains other than .com, which is still for after market sales. it's a bit expensive to buy at my current startup stage. what is your advice? by the way, the name of my startup is currently on top of Google since I am the one started using it for my startup.