𝘛𝘳𝘢𝘹𝘹𝘢𝘴 ℝℂ!

Recently got a used Xmaxx but had to buy new batteries. Bought them direct from traxxas. 2 new, 3s 5000mah batteries. Using the dual charger that came with the car, i charged them on balance the day they showed up. Tested out the car and when it slowed down, i charged them on balance again. A week later, drove the car again and once it slowed down, i put the car away. The next day i pull the batteries to charge them and they won't charge. One says voltage too low to charge and the other says wrong/unidentifiable battery. Any solutions here? Anything i did wrong? Should I just contact traxxes?