Gadget Time Bad service

Hi i purchased a mp4 player at your Canal walk branch on the 19/12/19 for my daughter for Christmas.. so on 25th my daughter open her gift and i put a memory card in for her so that se can use it the unit loads all most the whole day... On the 26st i put my wife's memory card in still doing the same thing loading the whole day... Because I stay far from Canal walk and couldn't get there to refund the unit and i did work the whole December.. i try to refund the unit they told me i can't because they have a 14th day refund policy... but the thing is still in the original package not been use they still don't wane refund me...