My nokia 6300 does not pick signals in office and while its in pocket..but works perfect at home with all bars..otherwise it just shows 1 bar and its hard to talk...

If the device has worked for you in other locations, the most likely answer is that you have low signal strength from your network carrier to your device. To test if low signal strength is the problem, try moving your laptop to another location, closer to the cell tower you think might be servicing you to see if it starts working. If your laptop connect software has the ability to show you the signal strength, look to see how many dBm the signal strength is. The larger the negative number, the worse it it. Below -85 dBM, you will have frequent drop outs.
-75 to -80 dBm should give you usable results. -65 dBM and lower should give you very good results. If you can only find the strength in bars, 1 or 2 bars is bad, 3 bars marginal, 4 & 5 bars useful to good. You can buy repeater devices which pick up cell signals and rebroadcast them, making them stronger for you laptop to pick up the cell signal. They usually have an external antenna port which you can put outside and high to help pull in the signal. Trees, hills, and rain all block and lower the signal strength between you and the cell tower. Distance is also a big factor.

I have tried to contact the service provider, they says this code is to be obtained from the hand set manufacturer and we are not providing "call barring services" for our network .

jumana st,
as u said about problem related to barring password. Only your service provider can resolve this issue.

Select Menu > Settings > Security

Disable call barring from there. however, you will need your barring password for this.

call barring password normally is 0000 or 1234 / 00000 or 12345

yes it must be a device problem give it to an autherised dealer for srevice.

Firstly, switch off your phone and put it on again if the location is different from where you used to use your phone, or, Check the network settings and select automatic to see all the available network on the area pick from all the list and if none of these worked then the phone may need to be work on l.e to be fix.

1.Check the device's battery level for at least two bars of strength.
2.If the battery level is low, charge the battery.
3.If the issue is not resolved, remove the back cover.
4.Remove the battery.
5.Wait 10 seconds.
6.Press and hold the W key.
7.While pressing down the W key, re-insert the battery.
•The device restarts and after approximately 15 seconds, the 'Recovery' screen appears
•Release the power button but *continue holding the home button*, for another 30 seconds.
Step
Thanks

is it possible to bar certain individual numbers on the nokia 6300

The only solution for 6300 is go to phone shop or nokia repair centre. Then ask for your phone to be flashed, you may need proof of purchase. Your phone will be fully cleared- back up your things first.