wifi switch is not turning on

Since you mentioned a Case ID, did you contact Apple Support about this issue?

This is a user to user forum, Apple can't be reached by posting here. We are all users here, just like you, trying to help if there are technical problems.

Did you already try the general troubleshooting mentioned in this article?

iOS: Wi-Fi settings grayed out or dim

iOS: Connecting to Wi-Fi - Apple Support

If this did not work, your device has to be checked by an Authorized Apple Service Provider or Apple, the problem could be hardware related.

iPhone - Contact Support - Apple Support