2 batterys and charger but just replace them again

I upgraded to a sony v about 2 years ago i have insurance an end had just pain with it from start to end! Its when you get told by the persoon thats there to help you that your suppose to replace your battery 3 time before you upgrade again! How is it posseble? i mean really? the phone is slow freezes, when it is on charger it tells you the charger is not a strong enough? 2 red lights and does not charger, its not even water proof anymore! even when the phone is switched off it does not last 8 hours how many batterys and chargers do i need to replace?<br> <br> <br> Please help!<br> <br>