You can be charged with this, but it will be difficult to convict you if they don't have evidence proving that it is you. You should hire a lawyer and figure out the best defense. There are many possible options, such as a Motion to Dismiss (if they don't have anything), or possibly a remand to a clerk's hearing. You might even need to take it all the way to trial.
I cover your area.
It is difficult to know without the specifics. In many circumstances, I would believe it is a beatable charge. However, I see cases in which a witness is intimidated by a third party and there is circumstantial evidence linking it to the defendant. Cases like those can lead to a conviction even though it was not sent by the defendant.
It doesn't matter who the phone belonged to, only who sent the texts. That's what they have to prove. Someone else could send threats from your phone and you could do the same from someone else's phone. They will have to establish that you sent the texts. They can do this from the content of the texts, sworn testimony from the phone owner or someone else with firsthand knowelege, GPS tracking, etc. Good luck. www.BryceFetter.com
You can be charged with a crime under the facts you described. The content of the text messages may give rise to probable cause to believe that you were the person who made those threats, even if the threats did not come from a cell phone with your name on the account. On the other hand, there may not be probable cause to charge you. The answer depends on the specific facts. Note: do not post the specific facts in a follow up to your original question - your postings could be collected as evidence against you. The fact that the text came from a phone number that was not yours will not automatically cause a charge to be dismissed.
If you have been charged with a crime, then step 1 is to get a lawyer. There may be a motion to dismiss the complaint for lack of probable cause in your case, but you still must go through the court process and convince a judge to dismiss the charge.
Disclaimer: This answer is provided for informational purposes only and it is not intended as legal advice. Additionally, this answer does not create an attorney-client relationship. If you wish to obtain legal advice specific to your case, please consult with a local attorney.