I can't defeat other colonies! Even when I destroy all of there settlements there still in the game. How is this possible? Can't they be destroyed for some reason???

They "respawn" to make it more interesting. :)

Is there any way to stop them from respawning ?
Or maybe give them some more stuff to respawn with and - most important - make them respawn somewhere else ?

Because of this: http://forums.civfanatics.com/showthread.php?t=294242
You could call it interesting, but somehow it doesn't feel right :lol:

Even after losing some colonies... the european powers werent so quick to give up.

Took the english a few tries to have a successful colony... french had a colony in rio de janeiro wiped out early on... but started colonies elsewhere.

Ive played the northwest map and wiped out 2 english colonies in the same place only to have them respawn another in british colombia on the west coast... however I suspect that this is because they had some scout over there found the colony.... different respawn locations would be the best fix for this, i agree.