Nokia 6131 not charging - help with unlocking

[pika_pika_pika]

My nokia 6131 doesn't charge - previously I had too move the small pin around in the charger socket and it would charge eventually if I positioned the phone at a correct angle it seemed - now it just doesn't charge at all and the phone is dead. Is this a problem with the charger socket on the phone or the battery? The charger itself works fine on other phones so is not faulty - it seems to be a problem with the phone. If it is teh charger socket itself - are these replacebale and at what cost?

Also, once it works again I'd like to check if the phone has been locked by the original provider (O2, UK) - i've read that these phones can only be unlocked by the original provider for a fee - is this true or can I unlock it myself now?

Thanks!