Pay or Not Pay?

Someone somewhere has sent me s letter or parcel and has under paid the postage.

The card that landed on my door mat asked me to pay the shortfall of nine PENCE and a handling fee if £1.

What would you do?

I am not expecting a special letter or parcel

I decided that after 18 days the Royal Mail can return whatever it is to sender. If it's important those people will send it back to me. If it's junk mail, i've lost nothing have I?!

DW