It's a pretty common problem and one Square Enix would like to address. The reality of the system is that they need to get more physical servers to house the extra districts and that takes time and money to set up. I think half the reason they went for the Private Quarters in FC houses was as a stop gap for the issue.

A lot of us are waiting for this but it's not something that is likely to be quickly resolved. That's just the reality of it. In the mean time your best bet is to try the Private quarters at your FC's house or just put housing ambitions aside until SE has a fix.

Invoking RMT though is going to start fights. Even suggesting it as an option is going to piss other forum goers off. There are many people who have earned their housing over time through legitimate ingame means. Try to storm into a thread sounding like your looking for a fight and more people will probably at least treat your post with more sympathy and maybe even it will resonate with enough people to get SE's attention.