People can't tweet at me or find me in search on Twitter...help?

I made a new twitter last week. However, everyone I talk to says they can't tweet at me. Only one person has been able to tweet at me, idk why just that one person was able to. I talked to a bunch of my friends yesterday who all said they've been trying to tweet at me and it doesnt work. I've had several friends who know alot about twitter go onto my account to see if my settings are right and they said they are, none of them have any idea what the problem is.