Access to Fill & Sign with Photography Plan

Hi All,

I have a Photography Plan and as part of the plan I get access to Adobe PDF services (so it says on the account management page anyway), including fill&sign.  I need to get a few documents signed by myself and others but after using this service for three documents I now get a message saying I need to upgrade my plan???

I find Adobe account management very confusing.  Why should I need to upgrade if it's part of my plan?

But if I do need to upgrade, is there an economical way to get this feature only for a short time so I can get my remaining 5 or 6 documents digitally signed?  It's something of a one-off requirement.