Transfer of data form to be signed by accountant that left the country, or we are *****ed

We have tried to cancel/delete the current administrator/owner of the SAGE 1 accounting package. It belongs to our previous accountant who has left SA for NZ and is not responding to any of our emails or phone calls. He needs to sign a transfer of data document for us as the owners of the companies. No reaction or response from his side. How in the world can we block this guy from our companies, and take back our business, if he would not respond to our requests??