To delete files from an Acrobat.com account, log on to cloud.acrobat.com/files using your Adobe ID and password. Then, select one or more files, and press the Trash Can icon near the top of the window.
I am sorry you are having difficulties. I do not work for Adobe. I moved your query to where users of the product can best answer your question. I am not an Adobe employee. I am a fellow user of Adobe products and help out in the forums answering questions when I can and moving questions that I cannot answer to the place in which users are most likely to get their question answered. Sorry I could not be more helpful.