Do not use Dawn Wing

I paid extra for next-day delivery from Cotton On. The package was due on Wednesday December 15. It's now end-of-day December 17 and no sign of delivery. I've called 3 times and written twice (no response to written queries). My calls are answered but no action taken. Cotton On should NOT be using this completely unreliable service - either Dawn Wing or DPDLaser, its new name.