Can't delete Office 365 calendar from my iPhone 5s
My password was updated on Office 365 and my Iphone calendar didn't reflect new meeting and I had changed the pwd on the phone. So now i am trying to delete it. I go to Passwords & Accounts, Exchange Calendars, turn the green key to blank against calendar and get the warning ' All Exchange calendars will be removed from your iPhone'. I press Delete from My iPhone and it just comes back with the green button next to calendars.
I have even tried adding an Exchange account but it says it is already loaded. Help!
iPhone 5s, iOS 12