Kids Sync Up watch not powering on

My granddaughters watch will no longer turn on. Initially, when it wouldn't turn on I thought the battery was really dead so I let it sit on the charger for a few days. Tried holding the power button down for 20s still no luck. Went to T-Mobile store to see about exchanging it, but they wouldn't do it because it had a scratch on the screen. Disappointed that I was paying monthly for a watch that no longer works I brought it home and noticed the two small pin holes. I poked a pin in one of the holes and voila the watch turned on and was fully charged. My granddaughter wore it for a few hours and then it died. Each time we charged/reset she got a few more hours out of it. Eventually it would last all day but required resetting every few days or so. Until about a month ago… now nothing works to turn it back on. I missed the window (before she scratched the face) to purchase the extra warranty. Not sure what to do… except continue paying for a watch we can't use.  :(

*FYI we’ve done the whole holding the button down, tried other outlets, and even purchased a second t-mobile charging base!