I heard this from a friend this morning and found a couple of articules about it this being one about a scam.
A card is posted through your door from a company called PDS (Parcel Delivery Service) suggesting that they were unable to deliver a parcel and that you need to contact them on (a Premium rate number). It's important that you do not call this number, as this is a mail scam originating from Belize.
If you call the number and start to hear a recorded message you will already have been billed £315 for the phone call.
If you do receive a card with these details, then please contact Royal Mail Fraud on .
I have also read
Each Christmas rumours circulate that an old scam has come back to life.
It concerns conmen trading as PDS Parcel Delivery who leave cards saying you should contact them on to arrange delivery of a (non-existent) package.
This line costs a minute and was registered to crooks hiding behind an accommodation address in Belize, Central America.
The important word here is "was". This scam was shutdown by the watchdog for premium rate phone services in 2005. This phone number is no longer in use. Although rumours of this scam re-surface each Christmas, it is no longer running (at least, not with this number).
So doesn't mean it couldn't have started up again with a different number.