using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

        var list = new List<Contact>

        {

            new Phone { Name = "Pavlo", Number = 1234 },

            new Email { Name = "Pavlo", Value = "1234@gmail.com" },

            new Phone { Name = "Mary", Number = 5678 },

            new Email { Name = "Mary", Value = "5678@gmail.com" }

        };

        list.GroupBy(x => x.Name)

            .Select(x => 

                    {

                        return new

                        {

                            Name = x.Key,

                            Phone = x.OfType<Phone>().FirstOrDefault()?.Number ?? 0,

                            Email = x.OfType<Email>().FirstOrDefault()?.Value ?? string.Empty

                        };

                    })

            .ToList()

            .ForEach(x => Console.WriteLine($"{x.Name} {x.Phone} {x.Email}"));

    }

    class Contact

    {

        public string Name { get; set; }    

    }

    class Phone : Contact

    {

        public int Number { get; set; } 

    }

    class Email : Contact

    {

        public string Value { get; set; }

    }

}