I want my parcel now!

I am very upset about the service I received from this delivery company. I placed an order in June for stuff I was gonna use for a function I am hosting in July next week. First my order got delayed for about 2 weeks then a refund was processed for one of my parcel in a form of a voucher without even finding out if I preferred a voucher or my money back, then I was informed my order would be delivered last week as it is already at the depot ready for delivery. Then I was told there was a delay it will be delivered this week. Now yesterday I received a notification advising of a cancellation due to regulations. Whose fault is it that my order is late? What should I do with the function I planned? I am fuming and want my parcel delivered to me as promised.