You can ask Customer Service to remove the feedback but it is unlikely.
Feedback is a useful public relations tool, but does not make any difference* on a seller's actual selling account.
What was the original problem?
Was the item never delivered?
Go to the Resolution Centre at the bottom of this page and open an Item Not Received dispute.
The first Suggestion is to contact the seller.
This is polite and the contact should be "My item has not been delivered. Please send a refund."
If you are not refunded in full, within 48 hours, escalate the dispute to a Claim.
Don't get into a discussion with the seller.
If the seller cannot prove delivery (not shipping, Delivery) you will be refunded.
Was the item Not As Described?
Same thing, Resolution Centre.
You will be told to return the item to the seller. The seller can only send you a Return Shipping Label if he is also in Canada, so you will be paying for this.
Use a Confirmed Delivery service like ExpressPost or Expedited. It will be expensive.
When the item is shown returned, you will be refunded. Keep on top of the shipping, since you have to show delivery to get the refund.
Disputes DO affect the seller's account.
Too many lost disputes and the seller's account is closed. Even a single loss can mean that the seller's selling fees rise or the number, value or kind of listings he can make are restricted.
*Don't buy from sellers with less than a 99% feedback. They are not going to improve.
