POSTNET LEMON TREE: Disgusting, rude poor customer service

I couriered my parcel to Newcastle through Postnet Lemon Tree, using overnight courier on Wednesday, 07 August 2019 and because Friday was public holiday I expected the parcel to reach its destination by Monday, 12 August 2019. Today, 13 August I checked and tracked the parcel still not reached its destination then I contacted Postnet Lemon tree, my call was answered by negative and rude consultant, she doesn't even want to listen and hear my side of the story and concern but expect me to understand that Friday was holiday that's why the parcel is not delivered. I wanted to understand what does overnight mean according to them or how does it work, if the parcel can't reach destination within 24 hours. My understanding is that an overnight courier is a mail or delivery service that makes delivery within 24 hours. Postnet Lemon Tree could have advised that their overnight service is not overnight as stipulated, but three days excluding the public holiday. I am not impressed!! Postnet Lemon Tree are ******** and consulted are rude with disgusting attitude and poor customer service.