Keep vibrating while charging

I had a mi band a LONG TIME AGO, i didn't use it for A SUCH A LONG TIME. When i connect the miband in the charger it is constantly vibrating, but, the band says it has 100% batery. However, when I unplog the band out of the charger it simply turn off like if it doesn't have batery. And i don't know what to do. I hope you could be able to help me