i replaced my smart keyboard and it worked for awhile but now it doesn't work most of the time. Now the special keys are wrong as well.

See >>> If you see an ‘Accessory may not be supported’ alert - Apple Support

If you are using a Smart (folio) keyboard, the alert is typical of a faulty folio keyboard. The electrical connections that pass though the flexible fabric hinges typically fracture - this usually resulting in errors and/or the on-screen notification that you see. 

The Smart folio keyboard itself is not repairable. The only remedy is replacement of the keyboard. You will need to contact Apple Support or your retailer to investigate warranty replacement.

You will find the Get Support link at top-right of this page.  Alternatively, you can initiate a support case using the excellent Apple Support App. If not already installed on your device, the App can be downloaded from the App Store:

https://apps.apple.com/gb/app/apple-support/id1130498044

A further alternative is to visit the Genius Bar at your local Apple Store, where the technicians will be delighted to assist. When visiting the Genius Bar, a reservation is recommended:

Genius Bar Reservation and Apple Support Options - Apple

Sounds like maybe a contact issue between keyboard and iPad smart connector. Did you try and clean contacts with a pencil eraser? I have had a few issues using my Smart Keyboard with freezing and becoming unresponsive. But I have found its typically dirty contacts or the keyboard had one too many folds or separations and damaged the conductive fabric ribbon cable in keyboard which is not repairable. If one of the contacts on the ipad is damaged that could also cause a issue.

Hi there saavery,

Thanks for posting in Apple Support Communities!

The steps below can help with the connection alert you're seeing with you're Smart Keyboard:

"Get help

If your iPad doesn't detect your Smart Keyboard Folio or Smart Keyboard or you see an "Accessory not supported" alert on your iPad, make sure there's no debris or plastic covering on the Smart Connector pins on the keyboard or the Smart Connector on the iPad. Also, try these steps:

1. Make sure that your iPad and Smart Keyboard Folio or Smart Keyboard are in the Type position and that you have the latest version of iOS or iPadOS.
2. Remove the Smart Keyboard Folio or Smart Keyboard from your iPad.
3. Restart your iPad.
4. Reconnect the Smart Keyboard Folio or Smart Keyboard."

This information can be found in Use your Smart Keyboard Folio or Smart Keyboard with your iPad.

If the issue persists after those steps, reach out for additional assistance here: Get Support

Regards.