can't get key FOB to work
 

I need some help in troubleshooting a problem. It seems my keyless entry no longer works. A few months ago it was sporadic and then I was only able to unlock the car. I changed the FOB battery and still no change. Now it doesn't work at all. I have to use the key to lock my door. From a distance the key fob worked last week and unlocked my door, but nothing after that.

Can you help me diagnose the problem? I would love to get keyless entry back

2010 Accent GLS 70K miles.