Returns not processed

I bought my son a pair of shoes from zando which did not fit. I requested a return on the 7/12/2017. And on the 11th I get an sms advising that collection was unsuccessful . To my surprise no one called me to collect. I then called the call centre and they arranged a new date. Shoes were finally collected on the 13/12/2017 . Today is the 20th and still my return has not been processed so I can exchange. This is the worst service I've ever received. When I call the call centre they say I might only get the shoes next year. In the meantime my son has no shoes to wear this year. I am never buying from zando again