Not delivered as promised

Ordered a wall sticker that was out of stock for the second time on my arrival at their store. Paid because it was promised i could have it before the weekend as this was urgently needed before my birthday. Told very clear i can collect on thursday or friday. Drive to the mall (40km away) especially to pick this up as I had NO COMMUNICATION that it would not be there as promised. Product not there. I get accused of coming there on the wrong day. No service whatsover offered to save the deal. I demanded that they courier it to me as they made the mistake in not letting me know about the order and nothing to be done about it.