Hi Boz,
Sounds like you are using one of the in-app purchased "Pro" versions of AutoCAD 360.
I'm not certain for the mobile app, if it's a one time charge, or, if it's an annual commitment so your best bet would be to contact the AutoCAD 360 forum folks directly and post that question on their forum located here.
This forum is for Autodesk 360, which i know can confuse people since their names are so close.
Please let me know if you have any other questions.
Can you just uninstall it and remove it from your app list on your on-line account? Honestly I have not done it before, that would just be my first approach.
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