If you had bothered to read the AP website over the Christmas break you would have seen it in multiple places that express post would take longer due to down days. It said quite clearly that the earliest delivery would be Monday the 4th. You won't be compensated because they had made the information public well before Christmas.

It is also well known that areas outside the express network don't arrive over night. Most of the time they take 2 days, but can take 3. It also states that clearly on the AP website, which as you have internet, have full access to. As it still arrived within their stated time, you are not entitled to any compensation. If it had taken 4 days, then yes, you would be entitled to a refund of the postage cost.