Why does Australia Post take 25 days to refund an unused ebay postage charge?

[crgcom]

I recently had printer trouble and printed 2 mailing labels. I cancelled the one I did not post and expected a refund but was told by ebay

that Australia Post take 25 working days to process the cancellation. What a ridiculous situation, my invoice is due an the full payment including the unused label will be deducted from my account. The refund will just sit in my seller account until my next sale. The onus should be on ebay to refund any incorrect charges. Cheers