Unlock code not accepted

[Anonymous]

I paid to have my pay monthly  wap phone unlocked about a year ago. I briefly used the phone on the Tesco network to make sure the phone was indeed unlocked and it worked fine.  I have since only used the phone on o2 but today wanted to try using another sim card (Lebara -    )

I am getting response invalid unlocking code or words to that effect.

What now?  Tried to get help via Chat earlier today but nobody seems to be available. Please help

Btw when I tried using the phone in Spain a few months ago  I was told by a local phone shop that the phone was not unlocked?? 

So how come I was able to use it with a Tesco SIM?

The phone is a Nokia C2  bog standard wap phone which otherwise serves me well.

[MI5]

It's not unlocked and a Tesco or giffgaff sim would work in it as they are both O2.
Did you request the code from O2 and do you still have the code?
If so, just enter it when you start up phone with Lebara sim in it.

[Anonymous]

Because Tesco uses O2 network - I do believe you  can use a tesco sim in an o2 phone, but not vice versa - so it appears the original unlocking failed I would say and using the tesco sim has given a false impression of it being unlocked.

[jonsie]

You should have received an unlocking code. Because you inserted the Tesco sim the phone would just accept it without asking for the code.

[Anonymous]

@Anonymous please follow @MI5 & @jonsie advice

[Anonymous]

Hi @Anonymous have you been able to unlock it?