Car won't lock - keyless entry

Neither of my key cards will lock or unlock my doors :/ will try changing their battery but can't see how that would affect both cards?

Bit of a pain as I can't lock the drivers door or boot at all! Anyone know how to fix it?
 
Use the built in key on the car. When you take the battery out you'll see the key, lock it using the passenger door. As for the reason why, I've no clue matey :S
 
Batteries could well be the culprit, so change those first, but if no joy I don't know!