why do we get shafted on the return policy which clearly doesn't work

[russkiy-dom]

what i cant fathom is why on earth ebay requests us to have a 30 day return money back policy when any time a buyer honest or not decides to use the money back guarentee or my return policy which i end up having to pay the return postage costs if they open a case verses when they just negotiate to send it back per my policy and also even when i proved the item was delivered and isnt defective just late they still keep it for free and get a refund.  excuse me but this is theft dishonesty etc as lets face it most people do the right thing and the rest scam us as think about this as well, if it doesnt arrive in time and people are reasonable they will wait or accept a partial refund or some other soloution but of course for me i get around 1-2 for every 100 sales which isnt bad but doesnt help either when i am a small time seller relying of ebay to make money in a foreign country as wages here in russia are **bleep** so i prefer ebay but all this makes life harder than it should be.  i say if you have a policy and someone opens a case for a defective item then ebay should make them adhere to the policy and pay damn it, if the item is late then ebay should at least tell the buyer if not recieved inside 60 days then a refund is automatically given to the buyer as how can we control the postal service or customs hmmmm