Month-to-date total cost (VertexAı) keeps increasing even though I delete all my projects and billin

Hello. I am a student and only use GCP for learning. But even though there is no project in my profile and
I have closed my billing account, the Month-to-date total cost (VertexAı) is constantly increasing. 
I tried everything but couldn't find a solution. I would be very happy if you could help me what to do.