I would like to do business with ISPs that have Warrant Canaries:
Like my offsite backup provider maintains:
However, in absence of this (I realize this is rare) your ISP should at the very least have a stated policy as to how they respond to warrants and "requests".
Turning off an entire block of IP space because some joker calls you on the phone is absolutely terrible. If you continue to do business with "serverloft" you deserve whatever you get.