How long before a case goes to arbitration?

A buyer, without any forewarning, opened a "Not as described" case against me over a puzzle which, he alleges, had one piece missing.  This resulted in ebay freezing my assets (no clever jokes, please) so I didn't have enough funds to refund him electronically anyway.  I sent him a rather frosty email telling him I'd have to give him a cheque because of the situation, and why the hell didn't he just contact me direct and I would have been able to give him a straight refund there and then without involving resolutions?

"Oh no," he replied.  "if you're in the habit of selling not as described goods, ALL MUST KNOW AND BE WARNED.  That's the whole point of eBay.  A cheque is no good I want it some other way."  From that point on detante between us NOSEDIVED!  

"Fine, if that's your attitude.  The money is on it's way in cash via Recorded Delivery, WHICH YOU WILL HAVE TO SIGN FOR.  Make sure you leave me negative feedback so that when I reply officially ALL WILL KNOW THE SCORE!"  You wouldn't believe the bad blood this has caused over one crummy puzzle.  It shows what a really nice man he is, deliberately setting out to cause the maximum amount of trouble possible i.e. setting out to get me official negative feedback which lasts a full year.

 

The long and the short of it is he received his money after having to sign for it this morning.  I sent him four photos as proof he had received it via track & Trace - I photoed the screen with his signature on it, plus an email saying will you now please inform eBay that you have received your refund and close the case."

 

I have heard nothing more.  If, through bitterness, he decides to  do nothing, even though he got his full refund - and a bit more, how long is it before the case goes to arbitration?  I'm not going to let this rest - he's a nasty bit of work who could well say he received an empty envelope just to spite me.  If he does, I've no proof I sent him £6.50.  Thus said, there is an old saying that runs very true - GOD PAYS DEBTS WITHOUT MONEY!  He'll get his come-uppance one day  - with interest.

 

One thing is certain - I'm such a bad ebayer selling dodgy items, I've got a feedback score of 328 while he hasn't even reached 90.  Little people stay little.