The easiest option, available on post phones, is to block the caller through editing your phone or call settings.
If you want to take legal action against the harasser, don’t block the number. Instead, report the harassment to the local communications investigations office or head to nearest police station. They might ask to record your phone calls for a specific period of time or to save the text messages you have received from the harasser, so that they can be used as evidence of the harassment. Then the case will be forwarded to the District Attorney who will send out a data disclosure request to all phone companies to find out which network the harasser is using. The data disclosure teams in the different companies will send the details they have on that number and then further legal action can be taken against the harasser.
If you rather not go down that route, there is another option. Most mobile providers also have a blacklisting service so that you can block the harasser from calling you. Another tip is to save the harassers number and set up call divert on your phone so that every time the harasser calls you, the call will be diverted.
‘Block from Mobinil’ Subscribe to the service by sending an empty message to 505, calling 505, or dialing #505#.
‘Vodafone Blacklist’: To subscribe, dial *7# and chose either ‘blocking the last received call’, or ‘adding another unwanted number’.
‘Etisalat Call filter’: To subscribe, send an empty SMS to 767 or log into your account.
You can also read more about Egyptian laws against sexual harassment here.