Shocking after sales service

Terrible after sale service! i ordered shoes that was too big. i requested a return 30mins after it was delivered. the Collection for return was sceduled for 19 Aug 2019, 27 Aug no one has collected my shoes. i have called Zando twice and their call centre just tells me its on the courier side which is Courier It and thats it..... this is the worst service i have ever had! no one is giving me answers or doing anything about my delivery