In my listing i put CASH only as my condition of sales. As ebay rules everybody should offer paypal(among 3 options) as a payment method. In my listing goods are only for pickup, no postage. If customer denied to pay cash and like to pay through paypal, can i refuse to accept that.    does my condition override ebays one?

Actually, in your description you have written CASH ON DELIVERY! which is completely different to Cash on Pick Up.

I wont accept paypal for pick up items,(though when listing i MUST add it as an accepted form of payment).
In my description, write something along the lines of: Cash only sale. Paypal will not be accepted for pick-up-only items. Thank you.
I havent had any trouble buyers because of this, yet. 🙂