CeX / WeBuy.com review: Not making a refund; iphone 7plus

Dear Customer services,
Thank you for your support about the recent case I opened. You were really supportive. However, my concern was not considered as I presented my case to the nearby store as advised.

I took the phone back where I bought it from, they couldn't do anything after letting me waiting for 3hours for them to test the phone. I I went back after three hours and they said I need to wait for more few days for them to test the phone properly. I decided to buy another phone which was more expensive than that thinking that they will make a refund after tasting the other phone. I wasn't given enough information and when I went there to get my money back they just issued me a voucher of which I can't use it as I bought already another phone from them.