I did all the courses for free, but TurboTex told me to pay $21. I don't know which course I chose for a fee. Plus, it doesn't pay. The error message keeps popping up

I did all the courses for free, but TurboTex told me to pay $21. I don't know which course I chose for a fee. Plus, it doesn't pay. 
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The error message keeps popping up.
Therefore, I would like to know why I was charged $21 and how can i pay my fee