Its quite simple, they stole the goods, and have an unfair clause in the contract.
Report the theft to the police.
Inform parcelmonkey in writing that the theft has been reported and you expect the loss to be compensated, informing them that their contract contains unfair terms (quote the correct law here) and that if they chose not to compensate for the theft then you shall issue court proceedings.
When they refuse, which they will, take them to court and win (you will if you play it right).
Simples.
Report the theft to the police.
Inform parcelmonkey in writing that the theft has been reported and you expect the loss to be compensated, informing them that their contract contains unfair terms (quote the correct law here) and that if they chose not to compensate for the theft then you shall issue court proceedings.
When they refuse, which they will, take them to court and win (you will if you play it right).
Simples.