I imagine if you trademarked it you’d mention it, that was probably your recourse. Some trademark protections may still be available, reach out to an IP attorne

I imagine if you trademarked it you’d mention it, that was probably your recourse. Some trademark protections may still be available, reach out to an IP attorney or 3 and see what they say. If an IP attorney tells you there’s no case you should consider trying to use this opportunity to grow your brand at their brand’s expense through writing and calling them out through social media. Probably feels bad but this is what you signed up for, plus they did you dirty here by ripping off the name you came up with and built up for the last decade.