Hi Roberto,
I'm sorry you had a poor experience and you felt that you were locked into a contract for Adobe Stock.
However, I would like to notify here that when you sign up for the Stock subscription you agree to certain terms and conditions and only after you agree to the terms, you can make the purchase.
When you subscribe to the Adobe Stock promo offer, it means that the first month is a free trial, Adobe doesn't charge you for the 1st month; the subscription billing actually starts from the second month. For more information, please refer to Legal subscription terms | Adobe
I have checked your account and noticed that you had signed up for Adobe Stock 10 images a month(one-year) plan on 31st of March 2018. Also, I have noticed that you have not used any of your licenses, so if you wish to cancel your subscription, please follow the steps as mentioned in the help document Cancel your Adobe Stock membership
You may also contact our support team Support FAQ: How can I contact Adobe for support? for cancellation and refund related requests.
In case you are unable to reach our support team through the above-mentioned link, please see Contact Support FAQ: Unable to reach support through the "Contact US" link
Feel free to update this thread in case of any additional questions.
Regards,
Twarita