Spiraling service!

Used to be really good and efficient. Now you get an email saying "your parcel is out for delivery", but "you'll maybe get it today, maybe tomorrow" according to the depot. When I ask why their service has deteriorated so much, she puts the phone down on me!!! I am in customer service. If i do this, I'll be out of a job! Calling head office, I held on for 7 minutes without anyone answering...unfortunately I have no control over which courier my supplier uses!!!