Estate Law Questions? Ask an Estate Lawyer.
If your attorney is also the trustee for the trust, it is going to make it more difficult to change attorneys, although it is usually possible (it really depends on the specific documentation in your trust that determines how a change in trustee can be made).
But in general, you do have a choice to be represented by an attorney of your choosing.
While we are obviously very limited in what details are available in this quick Q&A forum, I would suggest following up with your attorney again about the phone call issue with the college/university's attorney. Generally a client does not specifically authorize phone call vs. letter correspondence, and an attorney taking a phone call is not necessarily a significant issue. If it is a single phone call and the attorney did not take any action to impair your position or otherwise compromise your finances, I would recommend at least trying to follow back up again. You may have expectations for your attorney that were not entirely clear (if you wanted your attorney to refrain from taking phone calls that would be an extraordinary instruction, and certainly one that would need to be given separately), and if the issue is more specific to their failure to notify you immediately, check to see if there is a pattern of this, or if it was only once.
(I am not trying to release a bad attorney from bad conduct - again I lack sufficient knowledge of your case to be able to give you a formal opinion - but do try to match your expectations to what are more commonly found for legal consumers).