iPhone loops apple logo after battery replacement

hello i just bought a replacement battery because my old battery didnt last at all. so i bought your kit for it and watched a video on how to install it and i got it installed perfectly an everything worked, i put it back together and it turned on. it was at %50 and it eventualy died then when i went to charge it , all i got was the apple logo staying on for about 5 seconds. so i tried putting it into recovery mode but as soon as i unpluged it from the wall 3 seconds later the screen went black. so i retried and retried , im not seing a low power icon its just the apple logo repeting and repeating. so i opened it up again and reset the battery plug, and still kept repeating. i tried following this tutorial here ----Flashing white screen after battery replacement

but to no avail. they said it was a seating issue . which in my case it wasnt because it was working fine before it died, they also said if that didnt work it was a faulty battery

any help would be greatly appreciated thx