Video Doorbell will not charge

I am using the correct USB cord (tried a few- which while tested on other devices works fine) the door bell does not charge when I connect it (using the Orange USB that came with unit. I have Tried for 2 weeks to get the Video Doorbell ito charge. no pulsing BLUE light to indicate it is charging after 48 hours still nothing. Tried other cords etc but had the same result. Any ideas? Thanks Leonard R Dively