Worst service experience ever!!!!!!!

I ordered an item and paid for it on the 7th of December. It was supposed to be delivered on the 14th. After numerous phone calls, I was told it would be delivered on the 17th. I received an sms that my item is on it's way, the courier is coming, then I received an sms that delivery failed. Now I receid an email that they would refund me. How can they advertise items that is not in stock and if they had 1 on the way to me, where did it dissappear to? Worst service experience ever.