No delivery no communication

I placed an order on Mr price sport on the 2nd of December and and the last communication I received was on the 4th of December when they informed me that the order has been shipped, the order was expected to be delivered on the Monday 8th of December, till today there's been no communication and when I try to track the order on their logistics company City Logistics, it says order number is not found or doesn't exist. When I contact Mr price via their WhatsApp chat because City Logistics doesn't reply or answer their phones they keep saying "it is expected to be delivered by this date" and that date passes, I have to contact them again and they say again by this date also that date passes