Bt Verve 450 Phones Batteries Are Not Holding

[in a mo]

We bought the BT Verve 450 phones a few years ago ,a few months ago one of the batteries would not hold the charge ,I replaced it but the new battery also will not hold the charge .
Today another of the phones has a battery problem ,any idea what could be the reason for this problem also apart from buying new is there anything I could try to help my situation.
Thank you

[rccatnap]

Rechargeable batteries don't last forever and will gradually lose their ability to hold a charge.
If the new battery doesn't seem to charge, then the charger would be suspect.
However, you say the new battery will not 'hold' a charge, which indicates that the charger could be okay, but the phone could be suspect.
Does the new battery have the same mAH capacity as the old one? If it is lower, then it won't last as long anyway.
Radio repair shops are few and far between now, but a computer repair shop would have the test meters to check your charger for you at least.