The first one is good but it has a feel of suspense in the first segment "የተሳሳተ ስልክ ቁጥር ".In Amharic, in this particular scenario it's has to end the first phrase as the above translation "የተሳሳተ ስልክ ቁጥር ነው።" to avoid feel of suspense.

Besides i used a word "በድጋሚ" because it is familiar Amharic equivalent for "again"

In this translation, I didn’t use the equivalent word for the word “invalid”; The word I used, “የተሳሳተ” is equivalent to the word “wrong” but I used it because it gives more sense in Amharic. I believe that translation should be more focused on the message than translation word by word.