Crocs online 👎

I ordered 2 pairs of crocs online. Only one pair arrived today. When I phoned them to query this as these crocs are on sale, I was told they are having a problem with the online quantities. There are none in the warehouse of what I ordered. Is this now my fault? Asked to speak to a manager and was told they will phone me just after 12h00, still waiting. Phoned again at 15h00 to exhange the pair I did recieve for another pair, same price. The hentleman send me a link for exchange, but I can only get a online voucher after the crocs that I want to exchange reaches the warehouse. Can take up to 14 days. Will the sale then still be on? My only option now is to drive 80km to nearest crocs store to exchange it. This is pathetic service. Once they send me two different sizes of crocs aa well. And it cost ME, the customer money everytime. I doubt if I will ever buy online again. I would love an explanation and a free pair pair of crocs from them for all this trouble I have to go through. My petrol tomorrow alone will be the same as a pair of crocs. I even took screenshots showing that they do have the crocs I want in stock. How do you explain to a 14yr old girl thats birthday is on Sunday, she cant get what she chose herself?