User Activity

Just want to know what to do to retract a comment because I gave a rating to the wrong person. I accidently rated the wrong seller (don't know how this happened!!!) who is sending an item from overseas and I have yet to receive that item.. The seller...
What does it indicate if the seller does not reply to one's questions about a product? I have posted several questions although two after the sale went through but get no response.
I have recently bought and sold 2 items with good outcomes however noticed the buyer and seller did not leave feedback for me. I have already left positive feedback for these 2 members & expected the same in return.