Deleting gmail calendar from iphone settings

I have a dormant gmail calendar that I can't delete from my iphone. The gmail was used as a corporate account but now the company has recommended not to use the account. I don't see the mail but I can't get rid of the calendar from settings. In the settings the only option I get is to reset the password and I'm not allowed to use this account anymore. I constantly get pop-up messages to update from settings. How do I get rid of this from iphone?