feed back

Could you please explaine, I have recieved negetive feed back for explaineing what was stated in my add, I recieved a phone call to find out my address and advise they where comming to pick up item , all good at this stage, the next phone call was that I was told to post item. in add no postage, I stated to the person what part of the English lanuage don't you understand, negitive feed back recieved on my response. Ebay people spoken to agree that this was unfair. non payment for this item and a lot of stress. 

I thought I had sold a camera lens on ebay no comunication at all from winning bidder sale gone to your resolution centre no result, proposed purchaser 100% good feed back .I dont understand.