My website has email address for me to contact but few have suggested me to have an firstname.lastname@example.org email address.. Please clarify my doubt if someone can.
It depends on how you manage your mail and who is operating mail server.
If your e-mail server is hosted by your ISP, web-hosting company or service like Google Apps, you do not have to, they already do that. For example if you buy Google Apps you can set up your own email@example.com, the firstname.lastname@example.org will be redirected to administrators from Google, same goes with webhosting company or ISP.
If you have your own mail server, you should have abuse@ set up along with @postmaster and others. There is a lot of reasons for this, main reason is there must be a contact person when someone missuses or abuses from your domain and you want to know when this happen, I think nobody will take your domain, but your ISP will disconnect your server and reroute your IP if you will not respond in time.
Nobody is going to take spam or abuse for granted these days and no service provider is going to tolerate, if something bad like spam, viruses or other suspicious activity originates on your server, because they have rented it to you and most likely their name is in the IP whois contact database, usually with abuse@ e-mail.