Hunter 350 Chainsprocket

My bikes run about 13500km in over one and half year, now considering how bad my college roads were abd everything, my chain sprocket is ruined and i need to buy a new hunter 350 chainsprocket ( brass ) but i cannot seem to find any woth the same model, please help me find one and if any devs here, please do educate me if the one for thunderbird is the same for hunter. I need to make these changes as urgent as possible