What follows is personal advice, not legal advice. Do not take this as competent legal advice. Your best option is to consult with a local attorney.
Once you have a judgment against you for a given debt, the debt is yours, whether or not you have a valid defense. A judgment effectively validates your liability on the debt and erases any claims you may have that the debt is not yours. Ergo, seeking an injunction against collections on the judgment will do you no good.
What you need to do now, if you want to assert a defense to your liability on the debt, is to get the judgment set aside.
Every state has procedures whereby a default judgment can be set aside. Usually this is done by a motion rooted in a particular court rule. BEWARE: there are strict time limits! Usually, such a motion must be filed within one year of the entry of judgment.
You will likely have to show good cause for why you failed to answer the complaint and/or appear for your hearing. Additionally, you will probably have to file an "affidavit of meritorious defense," meaning you have to show that you have a defense to the claim (in your case, the phone was stolen and someone else ran up the bill).
This is a very complicated legal maneuver. If you want to do it yourself, you will need to research your state's court rules regarding the setting aside of default judgments and be DAMN sure that you follow the procedure to the letter. Don't rely on what you may find on the internet. You need to visit an actual law library and research a practice guide.
I would NOT reccommend attempting this without the assistance of an attorney.
As regards the ethical ramifications of the firm receiving the judgment in the first place, yes you do seem to have an issue. Attorneys are under an ethical obligation to obstain from filing claims where there is a viable question as to the validity of the circumstances. And the attorney does have a duty to ensure that he is not violating this rule by filing a lawsuit.
But that's a secondary matter, because it's not going to get you anywhere as long as there is a valid judgment in place. Your primary concern at this point is to get the judgment set aside.
If you succeed in getting the judgment set aside, the proceedings will likely start anew. If you get to this point, DO NOT default again! ANSWER the complaint, SHOW UP for your court dates.
Then, if you prevail on the second go-around, you can start thinking about FTC complaints, bar complaints, and what not.
Best of luck!