Problems with delivery

Ive got a parcel (trainers) out for delivery with Royal Mail / Parcel force. On Monday it was supposed to be delivered, I waited, no knock on the door and then an email to say missed delivery. Next day, same again. Rearranged for delivery via the app. Same again today. He's either knocking with a feather duster or not at all. I have not been left a card, and now when I try to arrange delivery it says I need the details from the card. I'm getting concerned this parcel is going to "disappear" at some point. How do I get this sorted? Any advice is much appreciated.