Poor service

Bought two wifi camera's from them on arrival the one camera was clearly one that was sent beck from prior customer. It was not working and the power cord has been cut. Logged a return with the option for a replacement. All went well until this moment as the camera cost is below the free delivery I must pay the delivery for the new camera because of them sending me a second hand broken one. That's poor service now if I send them an e-mail they keep telling me to order a new one but no option for free delivery.