Might need to be fertilized.

As long as there is a drain hole in the pot, you can't blame the pot for causing over-watering. That would be grower error, likely exacerbated by a soil inappropriate for the plant, which hates wet feet. The plant is particularly susceptible to black rot of major roots caused by Pythium pathogens. It demands sharp drainage. You can get it squared away (if it has a drain hole) by burying the pot outdoors in a likely spot - you can always move it. This method of planting (a variation of the pot-in-trench method) puts the entire earth to work as a giant wick to drain excess water from the pot. As long as you are reasonable and withhold water until you can't detect moisture in the soil with a finger, it's almost certain the limitations associated with over-watering will be relegated to non-issue status.

Kathy is probably right, too. I think I can see some chlorosis (yellowing) in the older/lower leaves. However, over-watering limits uptake of water, and therefore, uptake of nutrients ...... so it can cause the same chlorotic look that you might see as a symptom of a nutritional deficiency. As far as that goes, it could even be a pH issue, but my money is on over-watering as the limiting factor.

Al