They can just use all the cap missiles they'll be unloading from their cruiser fleet
In seriousness, I wouldn't think it'd be that expensive, but I would expect some kind of come-uppance from Ageira for messing them around. To be honest, I don't really know why they haven't already shut down their lanes and gates, given the war. Maybe the control centre was on Bonn (actually that could be a reasonable explanation).
Yoba, about Bretonia not getting any new systems, earlier today I made a related post here.