Linking a Canva Account

I began using Constant Contact a year or two ago and didn't try the Canva app for a while.  I imagine that the first time I tried it, it asked me for a Canva log in.  I likely used my personalCanva login.  (Obviously I don't really remember.)  I  subsequently learned that Canva allows nonprofits a free account.  My personal email is used in conjunction with that account as well as a couple others.  I don't seem to be able to access the "free" account when I click on the Canva link.  It goes directly to Canva with no login instructions.  I am still seeing pro images.  How can I change which Canva account I am linked with