New Webmaster Can't Get In

I replaced an old webmaster who set up a zoneedit account for, and we can't get hold of her, and we REALLY NEED TO CHANGE OUR IP, but we don't have access. I represent the legal owner of the domain, so how can we take care of this? I either need access to the account she set up, or transfer to my account so I can make changes to the IP. Please help, we've been ready to change servers since yesterday and every day we can't change the IP we are losing money. Please help.