OK, I have had it go right, and also horribly wrong.
First of all, log into your account, and do an RMA request, explaining why you are returning the goods. Once this is accepted, you get an RMA code, make sure this is clear on front of the package, and return to eBuyer - once there, and checked, they will credit back the item.
When it goes wrong - I have had RMA'd goods returned to me, because the monkeys there refuse to take notes or look at their system - enotes go unanswered for days, what someone says, another denies - so on and so forth. BUT I now make all my enotes FTAO my contact there, plus I now have a phone number for customer service
I had to return a processor and motherboard which detonated when I turned my PC on for the first time (yes I did set it up right ), and that went fine, a lot better than I expected since they could have blamed it on me and refused to replace it. Although it did take a few weeks to sort out, they apologised for how long it took and let me choose a more expensive motherboard than I bought as they didn't have any of the original one in stock
Quick up date for anybody whose interested. RMA was accepted, and is being collected from my office tomorrow FOC. I'll be waiting for a replacement though but should have it by the end of the week. new graphics card arrives tomorrow woot! Time to install some games!