Okay, There is no real answer to ebays totally bias feedback system. They are not particularly interested in fair. Although they try. Its difficult to administer such a monsterous process.
With non paying buyers its best to follow the process of filing a claim and then finishing it at which time a strike will be placed against the buyers name. If they continue this behaviour they will be banded permanently.
Ebay needs to trash the private setting on feedback profiles as it can be used to disguise the truth. As a neutral feedback does not count to a percentage of feedback score then a seller may have multiple neatrals for bad behaviour yet still have paid for items so there is no no payment claims against them and still they have 100% feedback.
Anyways I suggest you report the non paying buyer to the police e-commerce fraud squad who will follow this up regardless of the amount of money involved. Well in Australia anyway. I am in this process at the moment. Only thing I regret is not being able to see the persons face when they are contacted by the police in regard their fraudulent activities. I have also engaged a solicitor who believes that he will redeem my money and all costs involved in redeeming the money unless he will not charge me a cent for his services.  Needless to say if we are successful I will only get my 50 bucks back but the legal costs will be high  and passed on to the crook who did not pay. Send the message to those with lack of character.  People who are dishonnest need to be ruined. And then maybe they may learn a leason. Unfortunately these type of people don't often learn leasons. They will still find some way of blaming you for their own problems which they are soley responsible for. Thats their gig in life. And I feel sorry for them and their family and friends who have live with them. On the flip side I am a compassionate man and worry if the reasons for their activities may be genuine. Perhaps they are dead and here I am spitting on their grave. One recommendation is that you cool off before you make any rash decisions. Don't lower yourself to other peoples standards. Live your own ideals and peace will be yours.