Another person has used my iPhone and set up a gmail account importing all their contacts and emails. now all their 8000 emails are on my phone and I do not know how to get rid of them or their contacts.
Remove the GMAIL account from your phone first.Then navigate to “Settings > Mail, Contacts, Calendars” and click on iCloud. 2. Now make sure you move the slider next to “Contacts” from ON to OFF. Upon prompt, tap on the “Delete from my iPhone” button. Move the Slider contacts back to ON and it will resync all of your contacts.