I unlocked my Blackberry phone form unlockgenie.com. I am very happy to say that now I can use any SIM card 
I got the code very quick and the process is called remote unlocking. I had no problem with the code and it worked well.
I have a set of instructions to follow with me. This came with my MEP/unlock code and I hope this could help someone in unlocking their phone.
Instructions for unlocking Blackberry 9700
1. Remove the SIM card
2. Power on the phone
3. Turn off all Wireless Connections
4. Go to Settings.
5. Go to Options.
6. Go to Advanced Options.
7. Go to SIM card.
8. Type the letters mepd (you will not see text appear on screen while typing).
9. Now type mep2
10. It will say “Enter Network MEP Code”.
11. Type in the unlock code ( 8 or 16 digits ), press in the trackball to confirm.
12. If there is more than one code provided, type each one until the phone says ‘Code Accepted’.
13. Restart the phone (and re-enter SIM).
14. Turn your Wireless Connections on again.