guest who do not show up and do not get in touch


I need help. I am relatively new to booking. Please advice me on what to do in the future when guests book the apartament, keep the dates blocked, do not get in touch and ultimately do not show up. For example, a guest booked my place on the 2nd of July number of reservation 2124826703, failed to get in touch although I tried to contact her/him numerous times, and did not show up on the date of the supposed arrival. Obviously, I have lost a lot of business due to this reservation that never came thought.

Thanks in advance