iIs it right? or is it isn't?

For the pass 3 days it has been quite hard for me. It can be seen as I haven't updated for the last 3 days. It started on Saturday. I received a sms from a friend telling me that a guy called A told me that 2 of my friends told me to stop disturbing them and if I still didn't listen to them I have TO ANSWER to him. I was very very shocked and pissed at the same time as I know that I had done nothing to provoke those 2 friends until they would say that. So told A not to act like a gangster and put words into peoples mouth. And then he replied," you know she is my gf and you still ask for her phone and talk to her. You say i am gangster. You pick a time and a place. CALL ALL YOUR GANG.You don't dare say la NO B**Ls
Well let me ask this question. Is it wrong to talk to someone as a friends even if he or she has a bf/gf?
Is it wrong to say a simple hi to someone you know even though she has a bf or gf?
Is it wrong to have a simple conversation that doesn't go over the line?

I am not that sickish type or jerk that will snatch people gf la. And I know where I stand and will never go over the line I can assure you this.