I just purchased the VPN but installation failed. Is this a scam ? I am using IOS 12.7.6. How can I get my money back !!!

As stated on https://www.mozilla.org/products/vpn/download/ you need macOS 13.0 or later and for iPhone you need iOS 17.0 or later to run. As Mozilla VPN is a premium product you can use the form on https://support.mozilla.org/en-US/questions/new/mozilla-vpn/form to post a direct ticket for support. Note the form link will only load for a Mozilla Account that has the Mozilla VPN subscription.