You are completly and utterly missinformed about this - so stop throwing a temper tantrum and inform yourself first!

1) Your Grand Company doesnt matter when it comes to buying houses and apartments - you can buy one anywhere you like, given that your rank is high enough
2) There are 180 appartments per ward (90 for each division) - that makes 2160 appartments in each housing district and 8640 appartments total.
3) You buy the appartment at the appartment-complex in each district - so you might have to go around a bit and check all wards and subdivisions to find an open one!

One last thing you should know: appartments are basically the rooms you can get for yourself at an FC-house without having to be in and FC (that owns a house).