Hello 'nabil',
Do you mind a suggestion for future use? Since you have 60 days from when you buy an item in which to leave feedback, - in the event that the transaction did not go as well as you'd initially hoped, - don't be in a rush to leave a negative.
To that I would add, - never leave a negative without having contacted the seller first. At least give the seller a chance to sort things out with you. Some sellers genuinely want happy customers because happy customers are repeat customers and that translates into more money. Others simply wish to avoid a negative and will endeavour to placate you as deemed necessary.
Sure, there's always going to be those sellers who basically say "tough bananas", but as we don't have a lot of colour choice only leave a red circle when you have fully exhausted all avenues of recompense. Oddly enough there really are selles who give you no alternative, but certainly not most.
For today, however, you can send a nice note of contrition to your seller when you explain that you would like to revise that feedback to positive. I'm sure the seller will be delighted. For future reference, have a look at the following info page about all things feedback:
http://pages.ebay.ca/help/feedback/allaboutfeedback.html
