Hi Dan and a warm welcome to the forum
I am afraid that it is nigh impossible to change your IP once the IVA has been accepted, and I am sorry that you appear to be receiving a poor service.
If you can let us know which firm you are using and the identity of your IP, I will find an e-mail address for you to send to them directly. If you use a read receipt, you can tell when the mail has been read, and if they continue you ignore your requests for assistance you will have grounds for a complaint.
Regards, Melanie Giles, Insolvency Practitioner for over 20 years.
To have me propose an IVA for you, please visit:
http://www.melaniegiles.com/ivaEnquiry.asp
See customer feedback at:
http://www.iva.com/iva_companies/IVA_Advice_Bureau.asp