Can't connect to wifi since I upgraded to ios6

I can't use 3G when there is no wifi . Application such as what's app , browse safari and check mail also cannot . After I upgrade iOS 6 . This was occurs. Once I contact technical centre , the told I can't downgrade to original 3GS software . I hopefully they do some immediate action about this . Troublesome.

Does the iPod connect to other networks?

Does the iPod see the network?

Any error messages?

Do other devices now connect?

Did the iPod connect before?

Try the following to rule out a software problem:

- Reset the iOS device. Nothing will be lost

Reset iOS device: Hold down the On/Off button and the Home button at the same time for at

least ten seconds, until the Apple logo appears.

- Power off and then back on the router

- Reset network settings: Settings>General>Reset>Reset Network Settings

- iOS: Troubleshooting Wi-Fi networks and connections

- iOS: Recommended settings for Wi-Fi routers and access points

- Restore from backup. See:

iOS: How to back up

- Restore to factory settings/new iOS device.

If still problem make an appointment at the Genius Bar of an Apple store since it appears you have a hardware problem.

Apple Retail Store - Genius Bar

This problem?

iOS: Wi-Fi or Bluetooth settings grayed out or dim

If not successful, an appointment at the Genius Bar of an Apple store is usually in order.

Apple Retail Store - Genius Bar