Clan rights off
Here we describe briefly what you can do if you are in a clan but the founding member of the clan leader is no longer there and nobody has clan rights
Clan Admin go
A clan without clan rights is difficult to take care of, especially if the clan founder is no longer there because he left or was deleted and no one in the clan has rights. But it is not hopeless.
You could of course leave the clan, found a new clan and ask the members from the old clan to join. And then report the clan as 0-man clans so that it will be deleted.
Get full admin rights
The probably easier way would be to open a Support Ticket in the MoonID portal and get clan founder rights.