ISSUES WITH ICLOUD APPLE ID

I have an old apple id which i no longer use.

But it is still linked to my icloud account yet apple says they do not have this apple id listed.

In an attempt to delete it, I have to provide a password for it but apple does not have it on record.

I cannot upgrade my icloud storage preference because of this.

I also cannot link the the current functional apple id to my icloud since the old one is still linked.

WHAT DO I DO?