Upgrading JR Pass

Good Morning,

I booked my 7 day JR pass last night and by mistake I accidentally booked an ordinary ticket.

Is it possible to upgrade to the green pass? I replied to the email on the confirmation I was sent immediately after I noticed my mistake(roughly 5 mins after booking), and asked if it was possible.

I tried giving the contact number a phone call as well, didn't get through and left a message.

I leave for japan on the 10th of October and will be away till the 9th for work.

Any advice would be greatly appreciated