Was reading a blog post the other day and something was said that I couldn't agree with more.

life is too short to be part of a church that you don’t believe in.

Couldn't agree more.

If people aren't happy at your church, let them go.  Encourage them to find a new, doctrinally sound church to plug into.  Having them at your church doesn't help your church. 

Being a person that has left two churches I offer this advise to you, if somebody is leaving your church.

• Listen to the reasons they are leaving, but don't over react to it.  If they are leaving because your a snot nose jerk... don't react to being called a snot nose jerk, just let them leave.  Reacting doesn't help.  They are leaving so they likely don't want to hear spiritual advise from you.  At this point you've likely lost the right to correct them.  Leave it to God and to their new church. 
• Trust God.  The Holy Spirit is alive and well.  For all you know the Holy Spirit wants these people at a new church. 
• Pray for them.  I've said this many times in life.  Leaving a church sucks.  I've done it twice, honestly didn't have the full support of my wife either time.  But as a leader in this house she trusted my decision and in the end both decisions were the right decision to make. But pray for them.  Pray that they get connected.
• Don't talk bad about them.  It gets around.  Chances are they still talk to people in your church and things get heard or said to these friends that will get back to them. I know it has to me.
• Listen to the reasons they are leaving, and react to it! Yes, in contradiction to my first point.  Listen to why they are leaving, there is something to learn from it and adapt to in it.  Its almost never the leavers fault alone.  Both parties probably did many things wrong.  Learn from what they are saying, don't focus on their wrongs... but yours.
• Don't use their actions as justifications for your actions.  If they are snot nosed jerks, it doesn't give you the right to be one as well.  Chances are if they are leaving they are spiritually damaged a little and you shouldn't expect healthy things to come from them.  Rise above it.

Remember the people aren't your churches sheep.  They are God's sheep and God may be leading them to a new pasture to fulfill their purpose in live.