Does a divorce written in a mobile text message, with the intention of frightening and not divorcing, without uttering it, and occurring in a state of anger, take effect? And what is the Shar'i ruling regarding the number of divorces if it takes effect?

Writing a divorce by way of a metaphorical expression (kinayah) does not effect a divorce unless the husband intends it. So, if you did not intend to effect a divorce, but rather intended to threaten, then nothing is binding upon you. However, if you did intend it, then the ruling reverts to your intention:

If you intended to effect a triple divorce, then it counts as three divorces, and your wife becomes unlawful for you until she marries another husband in a valid marriage.

If, by your multiple expressions, you intended only to confirm the first divorce, then only one divorce occurs.