Online order not received

I placed an online order last week. On Friday, 25th June, I received an email stating that my order would be delivered on that day by 5pm. On Monday, 28th June I received an email that my order had been delivered. I have not received my order. I called the call centre yesterday and was informed that they would contact and revert to me. I have not received a response as yet and of course the managers are not available... What is my recourse here???