After I sent the item, the buyer left the negative feedback with below comments one day later:
"I would have never purchased an item 6-8 weeks for delivery..WOULD YOU!"
I state clearly it will take about 10-15 working days to deliver to USA, but this buyer left unjustified and vicious feedback.
One month later, the buyer open a item no received case without communication with seller.

It's a scammer and bad buyer who viciously leave negative feedback and open case to seller.

Beware of him