Cancelling a subscription- asks me to cancel 'additional subscriptions'

When I try to cancel my Pro subscription, I get a message at the bottom of the 'Feedback survey' pop up saying I have to 'firstly cancel my additional subscriptions' , and I can't go any further.  I don't have any 'additional subscriptions' as far as I know- I can't see any showing on the account.  Anyone know what's happening here?  All Zoom support doesn't mention this at all. Many thanks in advance