Using Chatgpt as a reference material

So I was reading this paper online and as I was going through it, I was getting some errors which said "your GPT subscription is over". I was so confused and was wondering why I was in this dead end. Finally when I was about to close the website, I clicked on the 'Back to chatgpt' button and it sent me to chatgpt which said "your subscription for gpt 4 is over" which made me feel like I've been scammed. <br><br>Has OpenAI scammed any of you??