Teen denying that she said things, SO and I disagree on how to address it

My husband and I took in our 14 year old 2 years ago and I need some advice.She will often say something and later come back and say "no I didn't" "I never said that" ect. Most often it happens when it's just the two of us (im a SAHP) but occasionally he will over hear it but he will not back me up when I bring attention to it because he believes that it should be ignored and that I'm petty to call it out and picking fights.I obviously disagree, I think that she's old enough to take responsibility and believe that if we ignore this behaviour it will only get worse, plus it can highly inconvenience me. (I do agree that some things should be ignored, like eye rolls and "FINE. WHATEVER'S")For an easy example, I might cook something and ask if she wants some, she will say no, and then when the food is ready and I don't dish her some she will get upset and say that she never denied wanting some when she 100% did. Then we get into a back and forth, normally its me "oh, I thought you said you didn't want any" "I never said that I was just talking about how I was hungry!" "OK well when I offered to make you some you definitely said you did not want some" "no I didn't!" Yes you did its fine, here is some of mine but don't deny what you said", "I never said I didn't want any" at this point I will walk away, and turn to my husband and say "I know for certain she said no when I asked" husband "Ya, I know, I heard her" Me "well why didn't you say something??" "I didn't think it was worth it" -_- . So how do we handle this? via /r/Parenting https://ift.tt/2Up36P0