Last year I tried to cancel my plan & as a result, Adobe sucked me into completing the annual plan by offering a few of the remaining months free of charge - I was still going to have to pay for something I no longer use, but it was a slightly less shtty situation. Then they were supposed to END IT at the completion of that yearly subscription, which was in May 2020. Guess what? They're still charging me and I can't contact anyone about it... NO the website chat box doesn't offer any assistance. I'll have to arrange bank and court proceedings if they can't refund my last few months and stop charging me. This software is like a parasite.
What you were given was a retention incentive to get you to keep your subscription, essentially allowing you to have a 15-month long subscription while paying for a year. Subscriptions roll over automatically. This is explained in the subscription terms you agreed to when you purchased the product. It is your responsibility to remember when the subscription ends and cancel it during its last month to avoid the cancellation fees.
This link provides information on how to cancel a subscription:
If you type AGENT into the chat box, you will be connected to a live person. Or you can perform a web search for "Adobe Customer Support phone number", which will provide you with a region-appropriate number.
Be aware that, because of the pandemic, wait times for both the web chat or a phone call are likely to be far longer (I waited two hours the last time I called). Please be polite and professional when speaking with the agent; they didn't set the policies although they may be able to help you with your issue, and like all of us they are under a lot of stress.