Taisiya Perhaps he started the connect while in the trial phase and it simple remained after downgrading.
You could disconnect the sub-account and try to open a joint-account and see if that prevents the upgrade-intervention.
However (!), you might risk not being able to re-connect your sub-account again because as Thijs mentions, the 2.99 e/month doesn’t (shouldn’t?!) support making outgoing connects.
Or perhaps your issue has already been resolved since your last post?