BackgroundGeolocation - not working

import { BackgroundGeolocation, BackgroundGeolocationConfig, BackgroundGeolocationResponse } from '@ionic-native/background-geolocation/ngx';

Basically I am having the issue when I do

this.backgroundGeolocation.configure(config)

Native: tried calling BackgroundGeolocation.configure, but the BackgroundGeolocation plugin is not installed.

Did some research and landed into the doubts.
Look at the code node_modules@ionic-native\background-geolocation\ngx\index.d.ts

There is
export interface BackgroundGeolocation {

There is also a
export declare class BackgroundGeolocation extends IonicNativePlugin {

Is there a problem on what gets imported. Is it the interface or the class?