1) Close, although you misspelled "visit" and need a comma after "soon". So: "Soon, I will visit you." OR "I will visit you soon." The second is more common.
2) The problem here is that because the phone is the subject of the sentence, a listener will think that the phone couldn't hear your call! Obviously, the phone can't do that, so we have to add you as a second subject and form two independent clauses: "My phone was turned off, so I couldn't hear your call." I use "so" instead of "and" hear because there is a cause and effect relationship.
3) Unless you're specifically going to the house, and not visiting the person, you should use "I will visit you". The house is implied. The most common version of this would be: "I will visit you next week. See you then!"
Next week I willl visit your house ,see you then / Next week I am coming over. ( to your house)