master reset on phone I had a iPhone that was in my ex boyfriend's name he took it from me before I could erase any of my contents out of it.

I asked him to do it and he won't. Now he is calling people I had saved on the phone.

Can I do a master reset on the phone without having the phone so he will stop harassing people that is stored in the phone?

I have tried to contact the Verizon store but they said nothing can be done.
If it is still signed into your Apple ID and has Find My Phone enabled, erase it via iCloud: https://support.apple.com/kb/PH2701