Sue them for infringement
I didn’t trademark my design and I actually kinda ripped it off a huge corporation’s logo from the 60’s. Maybe Zumiez got sued! Hahaha. Whatever, I made my money off it. Nothing lasts forever. I’m still selling it though, it just doesn’t move like it used to.
What kind of site are you using? Shopify? Wordpress?
Big Cartel lol
I helped my wife start a brand in 2017 and she smokes me.
She sells womens shirts for $45 each. Outsells me 5 to 1. Almost all online, some small wholesalers. She sells on Squarespace.
She invested in her own cut and sew shirts and found a niche market. Her shirts cost more though, around $13.50, printed and landed. My shirts cost $8.50 printed and landed, using Next Level blanks.