As you have discovered to your cost VM can charge what they like to call 0844 Numbers,and have done for some time now.
Their is already a few threads on this subject here.
See:
http://www.telecomforum.co.uk/index.php?topic=4164.0http://www.telecomforum.co.uk/index.php?topic=4040.0Another alternative is to use a cheap call supplier that offers freephone access ,or geographical number access if you have inclusive 01/02 minutes, like
http://www.18185.co.uk/mobilerates.php who offer both.
If you use these methods another advantage is you dont normally pay until connected,unlike 0844 where you start to pay when you here the charging announcement .