I had to pothos ivy that were beautiful when i bought them. They have begun to get dark brown circles in the leaves. What is the problem. Help

There could be a few reasons your seeing spots on the leaves. Maybe getting too much direct sun, indirect light is best. Over-watered or wetting the leaves by watering over them or misting. Seasonal change can cause some leaf spotting when the light becomes more diminished in the fall.
I'd Pull off any of the infected leaves and making sure the plants are in indirect light. Don't mist/wet leaves or over-water the plant.Let the soil dry out between waterings and see if doing any of these helps.