A charge can be brought against you whether or not the complaint is true.  However, being convicted of the charge is a different matter.  This is what trials are for.  Hopefully it won't get even that far.

Right now you need to hire an experienced criminal attorney in your area.  They can best advise you on how to defend against the charge.  If there is no other evidence, for example witnesses, photos of any alleged abuse, etc. the case will be that much harder to prove.

Note:  Just be aware that if your ex decides to try and drop the matter it is not up to him; charges can only be dropped by the prosecutor.

File an answer on the restraining order application and go to court and fight the charges (you can do this with or without an attorney).  You can also hire a private attorney or request a public defender to assist you on the criminal charge. 

Since I presume that the restraining order is in civil court it is unlikely that the public defender will represent you.  You can represent yourself or you can hire an attorney.  The attorney may have a criminal defense, family law or civil litigation background but make sure that they have experience dealing with restraining orders.\

The one thing you should not do is take this lying down.  A restraining order is a serious matter and it can have serious consequences.  For example when you apply for a job or an appartment the employer or the landlord may check out your record.

When you were served with the papers you probably received a date for a court appearance.  Do not blow it off.  If you need more time to prepare a defense or get a lawyer go to the hearing and ask the judge for more time.  He/she should give it to you.

When you say he "filed domestic violence against you" I assume you mean that he complained to police and that the D.A. is prosecuting you. There is much you can and must do. If the D.A. has not YET charged you, you would be well advised to hire an experienced criminal lawyer to contact the D.A. and try to convince them (with documentary evidence) not to even file charges. If you achieve that, or if charges are filed and then dismissed, or if you are found not guilty at trial, then you would be smart to follow up with a petition to find you factually innocent under Penal Code Section 851.8, the result of which would be to seal and then totally destroy the arrest record. In addition to destroying the arrest record, you might even get an order sealing and destroying the family court restraining order file with all its false accusations as well. I achieved this in one case in San Francisco, and it is possible where the accusations in both cases are the same, based on the same incident. You can learn more about factual innocence petitions by reading these articles on my website: 

http://lawyer-expungement.com/petition.htm

      And

http://lawyer-expungement.com/results.htm

    If your case is in the San Francisco Bay Area, you can also call me for a free consultation. I specialize in cases with false domestic violence complaints and in factual innocence petitions and in fact teach other lawyers how to do such petitions for their Continuing Legal Education classes. You should NOT let these accusations stay on file against you, as they can hurt you lots of ways: school admissions, child custody, security clearances, promotions, job hunting, professional licensing, and even participating in youth group coaching or counseling.

When you say he "filed domestic violence against you" I assume you mean that he complained to police and that the D.A. is prosecuting you. There is much you can and must do. If the D.A. has not YET charged you, you would be well advised to hire an experienced criminal lawyer to contact the D.A. and try to convince them (with documentary evidence) not to even file charges. If you achieve that, or if charges are filed and then dismissed, or if you are found not guilty at trial, then you would be smart to follow up with a petition to find you factually innocent under Penal Code Section 851.8, the result of which would be to seal and then totally destroy the arrest record. In addition to destroying the arrest record, you might even get an order sealing and destroying the family court restraining order file with all its false accusations as well. I achieved this in one case in San Francisco, and it is possible where the accusations in both cases are the same, based on the same incident. You can learn more about factual innocence petitions by reading these articles on my website: 

http://lawyer-expungement.com/petition.htm

      And

http://lawyer-expungement.com/results.htm

    If your case is in the San Francisco Bay Area, you can also call me for a free consultation. I specialize in cases with false domestic violence complaints and in factual innocence petitions and in fact teach other lawyers how to do such petitions for their Continuing Legal Education classes. You should NOT let these accusations stay on file against you, as they can hurt you lots of ways: school admissions, child custody, security clearances, promotions, job hunting, professional licensing, and even participating in youth group coaching or counseling.