Can't remove app association from inactive Google Play account

One of my Gmail accounts was modified to eliminate Google Play access. How can I remove K-9 as assigned to that account, as when I show K-9 with a new Google Play account it tells me “This app is associated with a different account, [account name]. To get beta updates for this app, first switch to that account in Play Store and join the beta.” But, I don’t have access to that Play account, and can’t remove the association!

Thanks for help, as I want to be a beta tester!

I think I solved the problem. I deleted the problem account from my phone, reinstalled K-9 from another Play account, and could then join the beta. I put the problem account back on and…no problem!