Cobra Remote Central Locking Problem

[sparey]

I've got cobra remote central locking on my polo, for some reason one of the remotes stopped working even though i just had the battery changed only a month ago, i've been using the other one and now that has stopped working but the battery in it is fine. So now i'm just using the key but when i put the ignition on the indicators flash like the hazards are on and i have to wait 10 mins for it to stop. Any way to reset the locking or something? I've got no idea about stuff like this so any advice would be appreciated
cheers