Bought one account from minecraft.net. Five months later the game is not premium anymore so I sent an e-mail to Mojang to fix this. Response back from mojang: Unless I have the "transaction ID number" from the e-mail that I received from Moneybookers, there's nothing they can do. Was able to find the e-mail. Here is what it looks like:
You have successfully made a payment to Mojang AB using your credit/debit card (MASTERCARD, xxxxxxxxxxxxxxx) on 21 Jan 2011.
The amount of USD 26.95 has successfully been debited from your credit/debit card.
This charge will appear on your card statement as a debit by: MB*Minecraft
Moneybookers Ltd., London, Registered in England and Wales no 4260907.
Registered office: Welken House, 10-11 Charterhouse Square, London, EC1M 6EH, United Kingdom.
Authorised by the Financial Services Authority (FSA) under the Electronic Money Regulations 2011 for the issuing of electronic money.
There is no ID transaction number so Mojang will not even try to help you!
Be careful, Mojang is a scammer and wants you to buy another account (price went up too!) if you loose your premium account.