Changed API in account here and on my site - now plugs won't update

the site in question is

Ive been paying for a long time and never had a problem till now after the api key update. Again, the new key has been copied to my site. The api update purpose was to disengage a site I no loner work with.

I get this: You have reached your maximum enabled sites for automatic updates. You may change which sites are enabled or upgrade to a higher membership level here »

Can you repair this for me please so I may continue updating my plugs as I have been