They are a hybrid calla and not hardy except in the most mild, almost frost-free winter climates.

It is also important to understand that these are really not houseplants although often sold out of season (they are typically dormant at this time of year) and in bloom (greenhouse forced) as a blooming 'gift' plant or temporary houseplant. Bot don't expect long term survival :-)

When grown indoors, they appreciate bright light but not direct sunlight, warm temperatures (70-80F) and high humidity (mist daily). Keep the soil evenly moist and fertilize weakly while the plant remains in bloom. Once it's finished blooming, it is advised just to discard the plant. The forcing and indoor conditions make it very unlikely to regain the energy necessary for the plant to survive long term and then there is also the lack of hardiness issue to deal with.

In addition to what GG has said those little pointy 'leaves' at the bottom often yellow and shrivel first. If you can keep the plant in the conditions GG suggests the yellowing and ultimately dormancy of the rest of the plant should be held off for a good while yet.

There wasn't much point in repotting them since they are best regarded as temporary residents although I have got one to reflower at the appropriate season after a period of dormancy. But in a cool greenhouse, not in the house.