Automatically received message in a response to a pay (ping-pong transaction)

A common idea for quick micropayments.
I send n XEM to a special account with checking threshold1 < n < threshold2;


    [li]if the special account is initialized, active and threshold1 < n < threshold2 is true, n XEM are send to the special account and I get a prepared encrypted message. If the account is single, it automatically turns to passive state.[/li]
    [li]if any condition is not satisfied, I get ERROR with full information about the special account.[/li]

    No intermediaries, direct contact of people.

    Any account can be initialized / deinitialized as special by asking:

      [li]threshold1 и threshold2 to check the condition of the sum[/li]
      [li]the sending message[/li]
      [li]permitted number of messages sent (single / multiple)[/li]

      Necessarily! The account can be edit.

      The message can be:

        [li]the password for the entrance fee videoconference / videolesson [yes, topical for me][/li]
        [li]link to download any paid content [yes][/li]
        [li]thanks for the donation [yes][/li]
        [li]any code [yes][/li]
        [li]datas of other cryptocurrency wallet (microexchange XEM - …) [maybe][/li]
        [li]etc [yes/maybe][/li]


        There is an important question of account's reputation. As its reflects, how to influence it.

          [li]within the NEM network?[/li]
          [li]outside the NEM network?[/li]