There is your problem , Cake art is terrible stuff , I made my first flowers out of it and they nearly always flop.
I make my own paste or I use Menina or the two mixed together.
To make your own , I use one egg white ( a small one ) I then add sifted icing sugar mix ( I don't bother with pure as I find that humidity makes it too difficult to work with) . I add the sugar spoonful by spoonful using an electric mixer , until the mix is at stiff peak and when you touch it your finger should come away clean.
Then add four level teaspoons of tylose powder ( at this stage it will go a little crumbly ) . Then get two level teaspoons of Copha or Frymaster and knead it through the paste until it is nice and smooth and elastic.
I use a little extra Copha ( just a very small amount on my hands) to coat the outside of the paste ball. Wrap in gladwrap , pop it in a freezer bag and in a ziplock . I find it works better if you fridge it overnight. It is fine out of the fridge for a week or so , I keep the extra I don't need in the freezer , not the fridge.