I will try, from a legal perspective. I am not an attorney, however I have a MSA in HR with post graduate studies in Employment Law. I have been applying employment law for more than 30 years in my work with military services, and 6 years of corporate experience post military service.
Regardless if you are in employment rights state or not, the act of firing you over the phone is not in itself illegal. This falls in the category of lacking taste, or being a bad boss. Many legal challenges have been made to firing by phone, third parties, and email. All of them are considered legal.
What is most important, however, is the reason for the firing.
If you were hired "at will", and the conditions of employment with your employer are "at will" then your employer may fire you without a reason.
With at will employment, either you or the employer can terminate the employment relationship without cause or reason, without incurring liabilities of any kind, or without notice.
You should know from when your were hired or employer handbooks if you are at will. The employer had an obligation to inform you of the conditions of your employment, which would have included that you were hired "at will".
Note: Generally, if there is no fixed term for the employment, then it is considered, in most cases "at will". However, this does not take away the employers obligation to inform you of the conditions of employment.
You should check your employee's handbook and the hiring documents you were given, including any contracts you might have signed, and look for the words "at will" employment.
Still, you may have a basis for a civil lawsuit and discrimination under the Equal Opportunity Act, or the Fair Labor Standards Act, for "wrongful discharge".
Even though, at will employment allows you to be discharged without cause, it does not mean you could be wrongfully discharged.
Employers cannot use at will employment to discharge an employee for retaliation, whistle blowing, missing work for jury duty, etc.
If you have no documentation that this is at will employment, then you might have a case for wrongful discharge. I see that you have attempted to speak with an attorney. You might find a different attorney, and this time approach them from the perspective, that you would like an initial consultation to discuss if you might have a case for "wrongful discharge". The attorney can come from the yellow pages, or you can find one at one of the following web sites:
Massachusetts state bar:
The initial consultation should be free or at a reduced rate. The fee will be worth it, because you will learn a lot in a 30 to 45 minute session.
Make sure you pick an attorney advertising employment law, wrongful discharge, etc.
NOTE: When you apply for unemployment benefits, the state will investigage the reason for the firing. The employer is sent a document to confirm your eligibility for unemployment benefits. Once you start receiving the benefits or benefits are denied, you can ask an unemployment counseler to review your file to find out what the reason for the firing was. If the unemployment office will not allow you to see the file, you can hire the attorney to find out for you. (Attorney's have a right to discovery)