Zando refund process is terrible

I bought a sneaker from zando 29 May 2018 and logged a return on 30 May 2018. I was told that my refund was returned on 12 June 2018. After a few days I called zando and spoke to a agent after waiting about 30 minutes to eventually get through. She told me that the refund would take 10 working days to reflect in my account. 11 days later I called again, waited another 29 minutes only to be told that the refund could take anything from 7 to 15 working days to reflect. It has now been 17 working days and no refund. Please help