The solution is making your own instance. You’ve basically got a copy of your own of everything you follow on the fediverse. If it goes down for a while, messages are indeed queued for a reasonable time. And even if you do miss them, things like comments, up and down votes will act as ‘reminders’
The landlord will then have to have the drains cleared and hear exactly what they found blocking it. This will improve your relationship with your landlord and they will feel happy that you decided to take revengeful steps against them which don’t really serve any purpose and are just a waste of resources. No way are they going to somehow claim back those costs from you