help with cnas

i'm an lpn having a long list of challenges w/couple of cnas, they like to tell me what to do and argue i mean argue or give me the dumb look when told what to do. i talk to them first, if no improvement i ask another nurse to talk to them since they are more familiar with the other nurse then, if still no changes i let the supervisor know and end of story until now when this cna said "don't do that...infection" to a pt while been toileted i asked her about it, the cna ignore me twice, i let the supervisor in turn know, after work i saw them two talking so i approached them and with a smile on my face asked "what are we going to do about it" the supervisor told the cna before walking away to go home at the same time the cna said to me "what are we going to do about what" i tried not to make it a big deal and emphasize the importance of communicating everything related about the pts for which she had the nerve to say that she would not tell me anything about a pt if she considers it to be not important. now not only have something with the cna but also with the supervisor whom instead of addressing it just walked away.