People must not do business with this company

They confirmed delivery for 'December 4, 2017 on or before 17:00' as we speak the time is 08:30 on December 7th, 2017. When I track my order, they now indicate that the delivery will take place on December 6, 2017 on or before 17:00. What is very convenient for them and inconvenient for me is that they do not have a contact number for me to ask and/or enquire. Just bad service.