Awful service from Zulzi.com

I placed an order on the 27th March the delivery slot available was for 28th March between 10am and 11am. Obviously the demand for delivery is high during this time. I waited until 15:40 on the 28th March then the order changed to delivered and complete. I have still not received my order. The call center was first unavailable and when I eventually did get through, I was number 4 in the line. When I got to caller number 1 I got pushed back to caller number 5. I have sent numerous emails to their support and info@zulzi and have not received a single response! I want a full refund immediately!!!