Did you try the online configurator?
If that's not your specifc model then choose the correct one:
Otherwise follow the instructions here carefully to configure your settings manually and double check them if they don't work straight off.
After making any changes to your settings always reboot or at least toggle airplane mode on and then off again to ensure that they take effect.
Post back with details if you still can't get it working.
Ideally screenshots of your settings or at least transcribe them and post them for review.
Hope this helps.