Your plant is related to Calathea, but it's the Never-Never Plant (Ctenanthe oppenheimiana 'Tricolor')
Curling leaves can be caused by numerous things and you don't mention where you live (state or country) but the problem is likely due to a lack of sufficient humidity. This plant requires consistent temperatures above 65F as well as above average humidity. To raise the humidity around the plant, sit the pot on a tray of moist pebbles, adding additional water as it evaporates.
Ctenanthe requires very bright, indirect light (no direct sun), consistently damp but not overly wet soil. Hard water that contains salts and minerals is detrimental to the health of the plant so if you are using tap water, you may want to switch to using distilled water or rain water.