Rule 28 [ Service by DX

the proper address for service includes a numbered box at a document exchange, or

there is inscribed on the writing paper of the party on whom the document is served (where such party acts in person) or on the writing paper of his solicitor (where such party acts by a solicitor) a document exchange box number and such a party or his solicitor (as the case may be) has not indicated in writing to the party serving the document that he is unwilling to accept service through a document exchange by leaving the document addressed to that numbered box at that document exchange or at a document exchange which transmits documents every business day to that exchange, and any document which is left at a document exchange in accordance with this paragraph shall, unless the contrary is proved, be deemed to have been served on the second business day following the day on which it is left.