Banning people doesn't work once you have above a certain amount of members...

I own a ginormous realm called Havok and I have 424 members! I got realms a couple months ago and I loved it until I got a couple of hundred members and I was unable to block people! Yes you heard me right!!! After I'd say 200 members or so I was unable to ban people. I'd ban him then he'll join my game, then I tried unbanning him so I Re-ban him and poof the person would disappear out of the player roaster- I.E out of the filter players. 
There's obvious reasons why this is a problem. I can't ban people!!!! Come on Microsoft help out the Minecraft community by fixing this bug for me and everyone else who will encounter this issue if they get a big realm!!! This effects all platforms!!! All versions!!!