Ionic-native contacts "plugin_not_installed"

I am using devApp and the @ionic-native/contacts plugin keeps telling me that the plugin is not installed, but I am sure it is. My plugin list is as follows:

$ ionic cordova plugin list
> cordova plugin ls
cordova-plugin-compat 1.2.0 "Compat"
cordova-plugin-contacts 2.3.1 "Contacts"
cordova-plugin-device 1.1.4 "Device"
cordova-plugin-facebook4 1.9.1 "Facebook Connect"
cordova-plugin-geolocation 4.0.1 "Geolocation"
cordova-plugin-googleplus 5.2.1 "Google SignIn"
cordova-plugin-ionic 3.1.3 "IonicCordova"
cordova-plugin-ionic-webview 1.1.16 "cordova-plugin-ionic-webview"
cordova-plugin-network-information 2.0.1 "Network Information"
cordova-plugin-splashscreen 5.0.2 "Splashscreen"
cordova-plugin-stripe 1.5.3 "cordova-plugin-stripe"
cordova-plugin-whitelist 1.3.1 "Whitelist"
ionic-plugin-keyboard 2.2.1 "Keyboard"

And I have installed @ionic-native/contacts. I am trying to do a find which is throwing the plugin_not_installed error:

import { Contacts, Contact, ContactField, ContactName, ContactFindOptions } from '@ionic-native/contacts';

constructor(
        public toastCtrl: ToastController,
        public contacts: Contacts,
    ) { }

agree() {
        var options = new ContactFindOptions();
        options.hasPhoneNumber = true;
        // options.filter = this.contact.cell[0];
        options.multiple = true;

        this.contacts.find(['phoneNumbers'], options).then(
            (contacts) => {
                console.log(contacts);
                let toast = this.toastCtrl.create({
                    message: "contacts: " + contacts,
                    // duration: 3000,
                    position: 'middle',
                    showCloseButton: true
                });
                toast.present();
                console.log("contacts: ", contacts)
            }
        );
    }

Same error in here, I rode yesterday that the cordova-plugin-contact is deprecated. Do you think it could be related with that?. Still researching

App freezes after fetching contacts (IOS only ). any one facing same problemt ???

Check out my response in another thread: