The support and manufacturing of Symbian has already been stopped mid-year 2013.Therefore from 31 December 2014 we don't support Symbian devices anymore.
Please refer to this post http://community.f-secure.com/t5/Security-for-PC/Mobile-Security-for-Symbian/ta-p/65063
The only possibility is a Hard Reset of your device through a specific key combinations.Please notice: A Hard Reset will delete all the data on your device (which will be lost if you don't have a synchronization or a backup)
Thank you for your understanding.
If I understand the question correctly, I think only your phone service provider can help you regain access to your mobile phone. If you want to regain access to F-secure Key, there is one way I know how. You need to have created and saved a "master password reset image" I think is the name. This is the only way to regain access to F-Secure Key. If you did not, it is unlikely you will regain access.
Contact the retailer who sold you the phone. Only they can help you unlock your phone.