Iphone 5c no power

Hia, need some help please. I have a 6 month old iphone 5c, recently it was dropped but was still functioning fine for a few days until i had a green screen with lines and it went off. Since then it isnt charging , tried to connect to itunes but itunes doenst pick it up when plugged in. Tried holding the home and lock button to reset this also doesnt work.

since this the phone has had a replacement screen and a new lightning port but this hasn't fix the problem. There still isn't any power going into the phone.

tried different chargers and no joy

the phone isnt water damaged.

has anyone got any ideas of what i could do as im sure the warranty is voided as the screen has been replaced by a local phone shop and not apple themselves.