We appreciate you writing in.
Sorry to hear that you are facing issue with changing the plan. Below is the link on how to change the plan. Please go through the information and I am sure you should be able to it.
Also, we have a Customer Support team that is 24/7 operational and you will get all the help that you require in order to resolve the issue. You must be signed in with your Adobe ID.
Please use the link below to connect with the Adobe Customer support via chat.
Please do not share any personal/confidential information like email ID, bank details, etc here. This is a public forum.
Let me know if you have any further questions.