Can't upgrade my business contract

I have been trying to upgrade one of my business contracts without success. On Monday the 2nd of March I spent more than 1 hour on the phone speaking to 5 consultants to upgrade my contract. I even spoke to a supervisor that was unable to help me. Finally I spoke to a consultant that seemed to know what to do and requested I email certain documents before the upgrade can be completed. Today I received a reply via email saying I need a signed upgrade document and that I have to restart the process and include such a document. I have been trying to call the call center today without any success - I get cut off every time I select to speak to a consultant. Where do I get the upgrade document!!<br>