Back stabbing STNA....HELP !!

SORRY this is sooooooo long..
I have been in LTC for 27 years......aid for 3 & LPN for 24 years. It never ceases to amase me that there is ALWAYS ONE IN EVERY FACILITY who thinks THEY have ALL the answers....geez, I wish I did.
My problem is one particular STNA who says she CAN NOT work with me. She changed her schedule so we do not work on the same weekend & cut back a day so "we do not work together as often". Last weekend I was off and she told the other nurse (who I usually work with) that she did not change her schedule because of her but rather because of me...just does not think she can work with ME. She tells other nurses & STNAs how she has had to change her schedule because of me & how I yell at her (never once raised my voice). I have spoken to her a couple of times about parts of her job she has not completed but I though that's what Charge Nurses were supposed to do.
The problems: I have caught her in 2 lies r/t patients....she runs to the DON with everything(DON has aids before nurses), she smiles to my face but OH so different behind my back, and she is constantly late but never does anyone say a word to her. The other nurse and I were "talked to" about how WE need to be nicer to these STNAs. Short of doing my work and their work too I am not sure how I could be nicer to them (her).
I have NEVER said anything degrading to her and have always tried to help out but I have my own work to do. She and another STNA are "friends" and both will tell anyone upfront " I have been here 3 years (a record for the facility), I know the policy better than you" so they both do what they want to do. If you tell them what to do you are "a bad nurse".
It isn't like jobs are plentiful around this area and I do not want to give up because of another person. We are on the same unit everytime we work together so I can not work another area to "get away"
I am just at my limit because I feel she just looks for things to tell the DON but when I talk to the DON about her the DON just tells me to be nice because the STNAs work hard.
After all these years this is the 1st major issue for me with an STNA & no support from my DON