我剛剛不小心切換到 從訂閱變成流量 可是我本身的訂閱還有20幾天 我切換不回來
Sorry for answering in English because we’re not offering technical support with other languages.
No problem. 
I’d changed your data plan to Subscription and reset your changeable date too. If you’d like to change it back I think you can do again.