Contribution points doesnt come back when fences expires

I dont know its a feature at the game but its not fair to keeping the contribution points after expiring, i wasted so much cp on my fences and i cant buy fences anymore. Like i said if it is the games feature i will understand but even after that, its not a good thing to waste cp on nothing.

 

When fence expire they dont disappear. They are transfered to warehouse at nearest city or main capital You just need to take them out and place again. All you loose are seeds tho.