First, delete or forget the network you already have set up. Then add your network as new. This is most likely what the message you are getting on your phone is telling you to do. When you set up the new network, you will see the following screen. Enter the network name, tap on the security section and choose the security method, then enter your network password. Make sure it connects. That's it. You cannot alter the security settings of an already configured network, just like in some apps you can't alter your credit card details, you have to delete the card and add a new one. I don't know what you mean by you will reject any suggestion of setting up wi-fi on your phone, because that's how you do it if you expect it to connect, and if you are going to ignore the proper advice, then you will never be able to connect. And nobody cares if you ignore their advice. Advice is given and a recipient of said advice chooses to ignore or follow it. We have no stake in the outcome.
