Can someone please tell me how charm works

[Furious1]

Hi all, Haven't played EQ in 18 years, been having a blast being back, however I'm running in to some reallyyyy frustrating play right now for the first time on my druid, I'm not sure what I'm doing wrong, everything up until this point, charm kiting has been working amazingly with few early breaks/etc. I'm 24, out in Everfrost trying to charm kite the mammoths, and all the ones I'm tagging are blue cons, nothing above that, and it's like these things have a build in frikken magic immunity or 75% less spell duration or something, I do not, for the life of me, understand. I charm, sit to med, 15-30s later, sometimes almost immediately, charm AND roots break. So then I'm spending more mana to re charm, as well as face tanking some hits because they want to resist my snares and roots as well, only to have the same process keep repeating, I have literally been spending all of my time trying to keep something charmed and med up mana/hp. I have only had 1 successful pull here out of hours of trying.

I've tried everything. Please help.
Sincerely, flustered but still so happy to be back.