The worst service ever from John Lewis

The worst service ever from John Lewis
The worst service ever from John Lewis, I bought a camera online had it delivered to Waitrose in Surbiton, returned it the next day unopened to Waitrose in Surbiton, as I decided on a different brand. I have waited 14 days for the refund, called them from abroad as I am travelling to see where the refund is and they told me they do not know where my returned item is and that I have wait 3-5 more days for an internal investigation and they refuse to refund my money.
I have an email confirming that I returned the camera through Waitrose giving ref numbers etc. Customer service said they would come back to me today, needless to say it's close of business and not word from them!!!!
Unbelievable appalling service!!! I am still waiting several days after my complaint and NO REFUND!!! It has been 3 weeks since I returned the camera! APPALLING SERVICE. I am suffering for their internal error!