I was given purple cala lilies in a pot, for valentine's day. Because I live in an apt I want to keep it inside ( I forget to water my outdoor plants). I have it in a South facing window, I spritz it every morning, & water it 2-3 times a week. However the flowers began dying with in a week and it hasn't seemed to stop. The leaves are still bright green. What am I doing wrong? Should I use indoor or outdoor plant food?

you aren't doing anything wrong. they will die, then the leaves will die, then you let them dry more, then put them somewhere where they will stay moist, but not wet, and will rest and chill. that is for when the leaves are completely brown.

then, after they chill for 3 or 4 months (maybe less, i'm not totally sure about calla's) you can take them out, put them back in the sunny window and start watering regular again and they will come right back for you!

Jif, out here callas are evergreen outdoors.
The leaves won't die down. New bulbs form and after that the plant blooms again.
Niecey, your calla can live in a large pot and would do well in a 10" pot or larger, but the plant will do best outdoors.
Forgetting to water might be a good thing (if you don't forget forever) as potted callas rot easily from overwatering.
I bought purple, yellow and pink callas.
Good luck !