using System.Collections;

Hashtable ht = new Hashtable();
ht.Add(25622348989, "James Moore");
ht.Add(25622348990, "Donald Taylor");
ht.Add(25622348991, "Edward Parkar");
ht.Add(25622348992, "Ryan Bakshi");

foreach (long key in ht.Keys)
{
    Console.WriteLine("Account No: {0}, Name: {1}", key, ht[key]);
}

ht.Remove(25622348990);
Console.WriteLine("\nAfter removing: ");
foreach (long key in ht.Keys)
{
    Console.WriteLine("Account No: {0}, Name: {1}", key, ht[key]);
}

kodingwindow@kw:~/csharp$ dotnet run
Account No: 25622348992, Name: Ryan Bakshi
Account No: 25622348990, Name: Donald Taylor
Account No: 25622348991, Name: Edward Parkar
Account No: 25622348989, Name: James Moore

After removing: 
Account No: 25622348992, Name: Ryan Bakshi
Account No: 25622348991, Name: Edward Parkar
Account No: 25622348989, Name: James Moore
kodingwindow@kw:~/csharp$