Bad Service/ Bad Communication

I placed an order on the 3rd August and it was due for delivery on the 13 August. This morning, 10 August I got an email stating that one of the items I ordered got canceled because of stock availability and they'll deliver the rest of the items on the 11th August. My query is that when I placed the order the stock was available and 7 days later it is no longer available. The first time this type of situation happened I was notified about one of the items that it was no available 2 weeks after I placed the order. The service is ****py