Q.Calla lily – tall leaves, short flowers
I have a calla lily in a container on my balcony, which was in bloom when I bought it and has continued to bloom for about a month. Now, however, the leaves are growing very tall and the flower stems are only growing an inch or two, hidden by the foliage. Is there something I can do to correct this?

Check the watering, they like to be moist but not sitting in soggy soil.
Try increasing the light but not heat.
Did you fertilize? To much Nitrogen can cause foliage to grow and not the flowers.
Here is a link to verify the growing conditions.