Got neg from buyer: what should I do(tripleflip18)

[GreenBean]

Our friend, tripleflip18 has a problem: give him some help,please

Hi, got my first neg feedback , for cheap item, no communication. Guy never emailed and i sell Real shirts directly from manufacturer for 15$. So my profit margin is very small. Anyhow can someone PM and help me remove the neg, its really hurting and
I wanna take care of it asap. Whats the best way to take care of it if he doesn't respond to my emails or phone calls