Leaving a group I never created

Hello,

Sorry for my reply. I'm only F-Secure user (their home solutions).

Just unofficial suggestions:

A while ago I got a subscription code from the group owner to renew the current subscriptons (safe and freedome) which I inputted right away. 

It is not clear about subscription status. Does it renewed as result (after such steps)?

I think that maybe it is not possible to do so with certain specific situations.

Then the group owner tried removing me from the group and adding me back in, but when they tried to send me an invite, the system insisted that I am in a different group and cannot be invited.

If you were added to group -> and you did use such subscription/licence design -> your subscription should be pinned to group owner subscription (and if it is expired - your licence is expired; also, if he removed from circle/group -> your subscription is also 'expired').

I haven't created a group nor have I joined a new one, and I cannot find any option to leave the group it says I am in (which includes only me). 

I think that such notification is about your own F-Secure Account (subscription).

So, potential workarounds are something like:

->> to contact official F-Secure Support Channels (chat as example):

https://www.f-secure.com/en/web/home_global/contact-support

and ask them for 'remove/close/delete' your account (all details of subscription, history and so) for further re-use your mail-address for fresh Account as part of group owner's subscription (and not as owner of own subscription).

OR just ask for advice about situation.

->> to use another mail-address for 'invited'-status (maybe possible to use something like aliases to your current mail-address).

In general, if you want to be 'part of another group' (to use someone's subscription as part of circle/group) -> I think it is good workaround (since subscription time is pinned to owner of subscription anyway).

Sorry for my long reply! And sorry if I wrongly understand your concern.

Thanks!