Somewhere along the line you have been grossly misinformed about the type of equipment needed to put on a professional karaoke show.
You need to regroup with an equipment upgrade, test it and learn how to operate it flawlessly.
If you have seen any karaoke shows and thought ..wow that looks easy. No the KJ was good and made it look easy. It's harder than it looks.
Dealing with crazy bar owners is only one problem. Then add in the drunks and jerks.
Take a step backwards and evaluate your situation. Come up with a solution. Maybe somemore time watching other KJs. Start talking to them and pick their brain.