Blackberry locked bought phone over the internet... now it says handheld is locked? Any ideas

Set a password on the device (Options, Security Options, General Settings, Password "enabled". It will prompt you to create a password). Lock the device or turn it off. Enter an incorrect password. Keep trying to enter an incorrect password. It will likely have you type in the word "blackberry" after about 5 incorrect attempts. After five more incorrect attempts it will likely have you type in the word "blackberry" again and warn you that it is about wipe the handheld. Do this and it will wipe the handheld.

You have to contact with your internet service provider.

In this case you need to contact that particular person from whom you bought the Handheld and ask him to contact the service provider for the Handheld unlock code and they will unlock the Handheld and you can use any Sim card in that particular Handheld.
I hope I was able to you.
Thank you for using Fixya.

On all the Blackberries i have seen - the password if you get it wrong ten times it just deletes all the personal data on it and resets it to the operator defaults.

so if you havent had a chance to use it much because its locked out, just keep typing the reset password wrong, type blackberry when it tells you too, and keep trying until it says Wiping Handheld.

You can reset the phone by going to Options > General Settings > Security > Blackberry button and wiping the entire handheld.
That usually does a pretty good job of clearing the handset. If that doesn't do it, then you might have to reflash it by going to the carriers website and redownloading the software.
One final thing - it might be the PUK code. If thats the case, then try putting your SIM card into the phone (if its a GSM Blackberry)

First thing you need to check wheather you're Blackberry Handheld is unlocked or not.
Secondly please check with the other sim card in your Blackberry handheld if it works then there is a problem in the orange sim card you need to contact the orange service provider.
If in case none of the sim card is working in you're Blackberry Handheld, you need to get in touch with those people from where you have bpught the Handheld.

check out rim's website www.rim.com then you will be able to grab the application manager.

Hit the symbol key and then the green send key to unlock your phone.....

I have got prolem with my black berry 8800 , i cant sent messages ang Handheld is locked

Error 507 on a blackberry means no operating system is found. You can try to restore your Blackberry to factory settings by using a Java loader found here:
http://www.blackberryhowto.com/content.php?article.32
You will not be able to save the data on your phone. Try this at your own risk and ask someone for help if you are unsure about the process. Hope that helped,
-WN