Hi
There are ways of removing iCloud locks but they aren’t all free unfortunately ;-{
There are services that claim to be able to remove it temporarily but I have never used one so that’s a bit of a gamble
What I would do is have the logicboard replaced by a professional ,just make sure they replace the logicboard with one that DOES NOT have a iCloud lock on it
If all goes well and gets replaced it shouldn’t have any more locks
As for going back to apple to get it removed:I would contact the carrier (o2,sprint,AT&T…)that the phone number was with as if you tell them your name they might be able to track down your details for you
Hopefully this helps
Any questions please ask
Thanks:-)