Sagem MC920 will not accept unlock code.

[Irishrover]

I have a code I got from Vodafone, the problem is the phone no longer goes to the "Enter Code" prompt.
I don't have the original sim, but the instructions from Vodafone were as follows:
Further to your telephone conversations with the Vodafone Pay as you Talk Helpline regarding the unlocking of your Sagem Handset, please find set out below the procedure and the unlocking code;

1. Insert the Sim card that you wish to use the handset
2. Switch handset on
3. Display will read 'PAYT LOCKED'
4. Enter 214832358
5. Press Validate (or OK if Validate does not appear).

Please note: If the code fails to work first time please contact us back as soon as possible. Do not repeatedly attempt to enter the code and procedure as you risk permanently locking the handset.

I entered a different code from the one above and now the handset will not let me enter another.
Do I need the cable now and some software to unlock it, if so is there a tutorial that I could follow as I am a complete novice.