Resetting Nokia PIN or PUK codes

I have a Nokia vodafone mobile phone, and logged out from my original PIN number because of too many attempts to connect with the wrong number. Now I am asked to reset it with entering a PUK code, which I don't have because I throw away the purchasing invoice where the PUK was. I have now no way out unless there is another way other than the one mentioned above.

Any assistance is grately appreciated!

Milena