Someone else's parcel delivered under my name!! Terrible Replacement Service!!

Order items 5+ days ago eventually gets delivered and the items in the box is completely different, not my items that I ordered at all! Now I need to submit photos, barcodes log multiple calls and it has been 2 days and the faulty package has not even been collected! They want proof and what not else...this is completely their fault, all I have done is open my ordered package to find that the items are someone else's order!!