I'm sorry you had a poor experience with Adobe Stock and feel that you were charged for the first month for the Stock promo offer (10 images per month one-year plan)
I would like to inform you that when you subscribe to the promo offer, Adobe doesn't charge you for the 1st month ( the first month is a free trial); the subscription billing actually starts from the second month. So in your case, you signed up for the Stock plan on 27th April 2018, so the first month will be a free trial and you will be charged from the second month that is on 27th May 2018.
For more information, please see Legal subscription terms | Adobe
I have also checked your account details and noticed that you have purchased an HD video. You can only purchase standard assets through subscription plans. Premium assets, such as videos, Premium collections images, and editorial images or videos, can be licensed on-demand or using credits from a credit pack.
Hope this information helps!
Feel free to update this thread in case of any additional questions.