Why wont they let me refund my harry potter wand?

i bought this harry potter wand from www.ebay.com.au and it doesnt even work. I've tried the petronus charm, wingardium leviosa, expelliamas, and even elloh hamora of my locked door but none of them worked. Im ashamed to say this and you musn't judge me but out of desperation, i even tried a forbidden spell on my sister, avada kadabra, but my sisters still alive :( Do you reckon that maybe the wand isn't the right one for me. Im bidding for Ron's wand but if it doesn't work im gonna be very disappointed and perhaps even give up wizardry