You need to talk to your attorney immediately. There is no court order that applies to your deposition in most cases. As to your mediation, if it is a required state mediation, as Ms. Cromley pointed out, your attorney appearing by phone can only be done with the permission of the mediator or the judge and is rarely given. There must be a very very good reason for your attorney to appear at either your deposition or the mediation by phone and not appear live. I do not know the reason why your attorney would want to do so and I will not speculate, but I cannot think of any good reason why your attorney would not appear live at your mediation and your deposition. You need to contact your attorney immediately and bring your very valid concerns to him/her and hopefully there is a good answer.
Disclaimer: the above does not constitute legal advice and is only an opinion of the author as to current law. You should consult an attorney with questions about your particular situation.
You might want to consider another legal representative. If your case is unimportant to him, you should find someone who has time to show up.
We give free general concepts to be helpful, but you should give ALL your facts to a licensed Attorney in your state before you RELY upon any legal advice.
If the mediation is a state mediation, they have to ask approval to attend by phone from the state mediator. Most state mediators do not allow the claimant's attorney to attend by phone, especially if the claiamnt is attending live. If it is a state mediation, you could contact the state mediator. However, if your attorney told you that with no explanation, it sounds like there is a lack of communication between you and your attorney, which may be the bigger issue.