I can't find a resolution to this on any other website so I came here. Bare with me because this is confusing.

So my husband and I broke our old iphone and couldn't afford to get a new one so we inherited his mothers iPhone when she passed away. We used that phone for a few months with no issue. I removed her Apple ID from the phone and used my own. Then one night my husband decided to install the new IOS update...the next morning we woke up and we were locked out of our phone. It was stuck on the activation screen demanding to have the phones Apple ID. I typed in my Apple ID, and it would not accept. It must use his mothers old Apple ID, but as I said she passed away and no one knows her ID. To shorten this up: we got locked out of that phone for good because after numerous calls and visits to both at&t and Apple "genius bar" we concluded that they considered his mothers iPhone stolen and would not unlock it without a receipt to prove purchase (the phone was bought in a completely different state YEARS ago so that was not possible).

My husbands grandfather went and got a new phone then gave us his other iPhone. I tried using my Apple ID on the new iPhone and it immediately tried using the find my iPhone and tried to lock us out of this phone as well...it powered down immediately and got stuck in a loop where the black screen with white apple kept appearing, but it never completely booted back up, once it got to the home screen it would turn off again instantly. By hooking it up to the charger it interrupted the loop long enough for me to go the settings and completely delete all traces of my Apple ID from the phone. After that it was still shutting off whenever we took it off of the charger-but eventually that stopped and now the only glitch is that our battery life always says 100% and appears to be perma-charged...
so now my Apple ID is forever lost and intertwined with that other iPhone, I can't use it on any other phone or it will freak out.

But my actual question is...can I check my iCLoud email on another phone without it locking up?? I have my iCloud email attached to several important accounts and without being able to check my mailbox I could be in a world of problems. I was wondering if I should try to just go to the mail app on iPhone, put my iCloud in and check my mail but I am worried it will cause the phone to glitch again. Has anyone else experienced something similar? I need to check my iCloud email but first I need to figure out if that will compromise my phone in any way.