Why is the 6-digit code system so poor?

[mu940971]

Since the required 6-digit code system from buyers was introduced, I've sold 3 items that required a code and only 1 of the buyers was able to see the any email containing the code despite checking and rechecking their emails. eBay assistant offers no advice other than "look again", so the items just stay in my account as "not delivered" despite me receiving the funds and the buyer sending me positive feedback. Everyone is happy except there's a pointless "not delivered" item hanging around.  Admittedly I can delete the details after 30 days and the item finally disappears, but this is such a primitive way to deal with the situation and it removes any record of the sale. So why is this system failing? - And, BTW, what exactly is the point of the code if it does not stop sellers withdrawing the funds?  

[john1297576]

 Code is supposed to prove delivery. Sellers may withdraw funds, but they are still liable for any refunds.

Through charge backs, refunds can be claimed up to 6 months after a sale, it would not be reasonable to prevent withdrawals,  in case a refund had to be made.