It is advised to create a Contact Class to handle the data easily first. However, without that, here is how I would accomplish the database entry task:
Custom SQLiteOpenHelper Class:
public class DBHandlerTest extends SQLiteOpenHelper {
    public static final String DATABASE_NAME = "database.db";
    public static final int DATABASE_VERSION = 1;
    public static final String TABLE_CONTACTS = "contacts";
    public static final String KEY_ID = "id";
    public static final String KEY_NAME = "name";
    public static final String KEY_PH_NO = "phone_number";
    public static final String KEY_MACID = "macid";
    public static final String CREATE_CONTACTS_TABLE =
            "CREATE TABLE " + TABLE_CONTACTS + "("
                    + KEY_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, "
                    + KEY_NAME + " TEXT(255) NOT NULL, "
                    + KEY_PH_NO + " TEXT(255) NOT NULL, "
                    + KEY_MACID + " TEXT(255) NOT NULL" + ")";
    public DBHandlerTest(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }
    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL(CREATE_CONTACTS_TABLE);
    }
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("DROP TABLE IF EXISTS " + TABLE_CONTACTS);
        //re-create db
        onCreate(db);
    }
    public void insertContact(String name, String phoneNumber, String macID) {
        //create db instance
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues contactValues = new ContentValues();
        //get the values
        contactValues.put(KEY_NAME, name);
        contactValues.put(KEY_PH_NO, phoneNumber);
        contactValues.put(KEY_MACID, macID);
        //insert row into db
        db.insert(TABLE_CONTACTS, null, contactValues);
        db.close();
    }
}
Implementing the method:
DBHandlerTest db = new DBHandlerTest(this);
db.insertContact("test@test.com", "0800-123456", "test_id"); 
db.close();