Hi there
Not eating pellets for a few days won’t cause too much harm. Adding granola and muesli style mixes to her diet is likely to cause more harm than good and may lead to soft poops or even diarrhoea. It’s better that she’s just eating her hay for the time being, give her just a plain pellet (a small amount fresh eat day, even try hand feeding them as treats a few times and day) and she will learn to like it. Sometimes bunnies just refuse to try things but then when they do they learn that they like them.
While bucky&bailey is correct that rabbits don’t need pellets to be healthy, for a young growing rabbit that likely hasn’t been transitioned onto eating a wide variety of healthy greens yet, I do feel at least some pellets are important to help maintain healthy growth.
Long story short, stop feeding granola/muesli/hamster mix. She will be fine on just hay and water until she learns to like his plain pellets. 