Need help to configure plans

Hi i need some help in order to configure my process :

I have 2 groups of plans : artists and pros

when user subscibe to my site, they get a free plan thank to profile based plan (here i don't have any problem).

Then if they want to subscribe to any plan, it's possible only by using the "upgrade" (i don't want to allow my users to subscribe plans other way then by using the upgrade button, to avoid them to subscribe any plan in parallel)

But the problem is that when the subscription expire, i can't give them an another free plan. I have tried, by using Asign plan (in automation), but the problem is that when user make an upgrade it automatically create a free plan in parallel!


About pros plans :
here i witch user mannually after they give me some informations about them, but the process is the same, when their plan's expires it should create a free plan for them

In abstract this is what i want to do :

Free plan (on subscription) - > then user upgrade to paid plans -> on Expiration (they should have a free plan again)
can you tell me how to do that?

Regards