UPS - I ordered a toy for my grandson with whom I was spending Christmas with on December 19th with 2 day shipping
I spent all of Christmas eve tracking a package that I ordered through Amazon (2 day shipping) because according to UPS it was "on time". I received notification around 4:00 pm that my package might be delayed.
It was too late for me to get anything else because my grandson was coming at 5:00. He is 4 years old and I was devastated to have to tell him that I did not have a present for him. Our Christmas was ruined.
I called ups and they blamed amazon for not getting it top them on time. Amazon, however said that they sent it out on December 20th.