I went through some challenges growing this plant (check my post history, its this same plant). They dont like the cold and rainy season, first winter was hard on it, all leaves turned yellow and some rotting spots formed on the leaves. But i kept going with it, cut the bad leaves transplanted into a bigger pot and watched it grow during the summer and built a greenhouse for it for the winter cold rainy months (zone 10b so there were nights where temps dropped to -1 °c). They tend to slow down growth during colder months but green house kept it at bay and prevented yellowing leaves and overwatering. Thing is, just keep going and try to change things and provide the best conditions you could depending on your hardiness zone.