Dpd Laser threw away parcel

Oh my word! Dpd Laser picked up a Zando Return from me on Tuesday 6 Feb, almost a week ago. The parcel is still not back with Zando. I emailed Dpd Laser a few times, but no reaction. Every time I phone them, I am told the parcel will be delivered very soon! This parcel is gone, I am sure of it. And in the meantime I cannot get my refund, because the couriers threw away my parcel!