Flex blinks in the charger but is dead once removed

[EJV624]

My Fitbit Flex was originally purchased for me as a gift from my daughter for my bday back in 2015. In 2017 I had problems with the tracker not tracking so I contacted support and they sent a replacement which was great.  Now 3 years later the tracker doesnt seem to hold a charge.  When I place it in the charger the first light blinks and eventually all lights as if it is fully charged. Also while it is in the charger I can see the device and sync it with phone app.  However as soon as I remove it from the charger it goes dead, no lights when tapped and can't be found from Iphone SE  App to sync.  I have tried cleaning the charging connections which i doubt is the issue since it does blink like its charging and I have even done the reset sticking paper clip in the charging station when the tracker is in and i see gives me 4 lights when I do like it reset..  My assumtption is the tracker just can't hold a charge any more after just 4 years.  Anyone have similar issue or any suggestions on what to do? I don't assume there is some battery in the tracker that i can replace and I just need a new tracker ?   Any help would be appreciated. 

[NellyG]

Hi @EJV624 I think you are right - the battery has u fortunately died. The batteries are not replaceable so the only option is to buy a new tracker. HERE is a link to the Fitbit Store.