Hey! Thanks so much for these replies.
They are not selling anything, no products, they just have a donation page set up, which is super misleading for my customers, as they think it's me. I got so many messages from my customers about this as they almost gave her money. I also DM'd her and sent her a nice message explaining my situation, and she just ignored me and kept posting stories.
I talked to my lawyer and she said it's possible to trademark my username if it's my brand, in this case my art and my store. So I will be doing that soon. She also told me I should buy a domain name and I just finished doing that. Still no reply to my second message to ko-fi, so I'm assuming they just don't care. As long as they get the money right?
Anyway, thank you everyone who gave me advice and took the time of their day to reply to my post. I appreciate it a lot <3