Hello - i went through this myself, i emailed T-Mobile and asked if they would give me the unlock code, i didnt mention money at all.
I got my unlock code, free of charge from T-Mobile, but waited nearly 2 months to get it.
I used this email address to contact T-Mobile:
customerservices@t-mobile.co.uk
Good luck, its a long wait, but it should be free, mine was!!
Regards
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