Hi Marty E. Rankin
Welcome to Microsoft Community.
I realize that you've encountered a problem with " How to turn off Microsoft Defender VPN ", and I understand how you feel. Don't worry, I'll do my best to help you.
According to your description, your question should be about turning off the VPN in Microsoft Defender on iOS. Generally, you can turn it off by opening the app and clicking the switch button in the "Privacy Protection" column, or in iOS settings, go to "General" > "VPN and device management" > "VPN" and manually turn off the VPN.

Based on my personal experience, your problem may also be that Microsoft Defender's VPN is repeatedly reopened after being closed. If this is your problem, just go to the "VPN" mentioned above, you should see the Microsoft Defender's VPN configuration, click the "exclamation mark" on the right, and turn off "Connect on demand". In this way, Microsoft Defender's VPN will not open automatically, but will be opened manually according to your operation.

I hope these suggestions have been helpful to you!
Feel free to let me know if you have any other questions or need any further help.
Best regards
Adrian.C-MSFT | Microsoft Community Support Specialist