Permaban due to abusive language - account lost forever?

Not likely, but nobody that has responded to you works for Blizzard. Even a Support Forum Agent who may respond here can’t tell you for sure.

The only way is to open an appeal. If you have reached the point where they say the decision is final and future communication will be ignored, then there is no hope.

You can open a fresh appeal immediately after the last appeal has been answered.

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