Hi I'm Joel and I look forward to assisting you today with your question. Have you tried signing out of iCloud on the troublesome iPhone, then signing back in? Cheers Joel
No worries, seems you tried most things. The error about locked for maintenance, is that presented on the iPhone itself? Does it ever alternate and display any different errors?
Hi mate, I've done some more research into your issue. See this link. Seems quiet a few others are also experiencing similar types of issues. Since you have covered most of steps in trying to regain access, have you also logged a support ticket with Apple? Cheers, Joel
No worries. Let me know if I can assist with anything else. Cheers, Joel