Worst Courier company error

Worst Courier company ever !!:

I get a message: We couldn't complete your delivery.

When call I wait for 35 minutes to be answered. When I answer they explain that they have a backlog since Black Friday (Today is 8 Des) When I ask when the package can be delivered they can't tell me saying something like 9 days - this after delivery is guaranteed 3-4 days

PS: I use multiple courier companies, and promising a delivery without having capacity to deliver the service is unacceptable. There is value in the products being delivered.