I have a model that I load from an API to a typescript model

export class Customer{
    constructor(
        public customer_id: number,
        public first_name: string,
        public last_name: string,
        public email_address: string,
        public phone_number: number,
        public user_name: string
    ) { }
}

And in the service I compare the users obtained from the API with their role to add the attributes of the Customer

import { Customer } from "../models/customer";
this.users.forEach(user => {
            if(parseInt(user.role_id)===1){
                let customerAux = this.customers.find((customerAux) => customerAux.user_name === user.name);
                if(customerAux){
                    user.first_name = customerAux.first_name;
                    user.last_name = customerAux.last_name;
                    user.phone_number = customerAux.phone_number;
                }
            }
        });

And it throws TS2339: Property ‘user_name’ does not exist on type ‘Customer’. [plugin angular-compiler]

I tried make a cast of type customer but it throws the same