Any notice, demand or other communication hereunder shall be sufficiently given provided that it is written and delivered by hand or sent by courier to the addressee at its address as stated herein or notified from time to time in accordance herewith and such notice or demand if sent by courier shall be deemed to have been served at the expiration of 4 (four) clear days after it is sent and in proving service it shall be sufficient to show evidence of receipt by or on behalf of the addressee at its address.