When you cancelled, did you get an email confirming this? If not, then you probably left the multi-stage cancellation process at an earlier step, instead of proceeding to the end.
It would be useful if Now sent our emails warning of this to everyone who starts a Cancel, but bails out before taking an official Exit, but they don’t.
Another good check that you have really cancelled is to go back into the Membership, and check it is no longer showing an upcoming payment for the next renewal date.
If it is showing such a payment, then this warns you that you never completed the Cancel. Or conversely, no upcoming payment shows that you did Cancel successfully, even if you never got an email
How did you manage to stop the payments, by the way? Normally, you have to rely on Now just not invoking the CPA debit again….
Where did you take out the membership(s), sounds like it was through the app. Which means they are tied to your App Store like iTunes or Google Play.