Bad service

Ordered shoes from ZARA on the 26th November, delivery date was scheduled to be the 6-7 th Dec, come that days no delivery and when I tried to track , it’s written they were unable to deliver -no reason as to why.. now I try to check on the ZARA website they say the 9th -13 December

I tried to call the number of the courier however it does not go through, this is bad service