Trying to manage plan but keeps giving me "Sorry, we could not change your plan. Please retry"

and to continue the above...there are 2 ways to contact adobe support; chat and twitter (now x):

chat:
if you have or want to purchase a subscription, use a browser that allows popups and cookies
and click here, https://helpx.adobe.com/contact.html?rghtup=autoOpen
in the chat field (lower right), type AGENT
be patient, it can take quite a while to reach a human.

twitter/x:
tweet @AdobeCare

p.s. if you're contacted by anyone (via email or private message), it's much more likely to be a scammer than an adobe representative.

Hi moisesm78787024,

We hear you! If you're unable to change the plan from your Adobe account, kindly contact support for help. You may use this link to contact support: https://adobe.ly/48DpmeR.

Hope this helps! Do let us know the outcome.