@Assemblerz
As far as i know
The relisted item has to sell when relisted.
The insertion fee is not credited immediately , But Credited if the item sells the second time when relisted.
Further you can't use Turbo lister , but relist from the item page itself .
Also note the relisted item's price can't be increased , Neither can the duration of the auction Or its format be changed.
In short the item has to be relisted in same format and same price or lower.
By the way this is not only for non completed sale but also for any item that does not sell , you do get a second chance.
I have used this on international site and am sure the fee gets refunded automatically if the item sells , But still
since you say .. i guess we need to check this out
Thanks for the enlightment :)