Hi, I'd like to help you with your question.
You said in your problem description that your child is beginning to have issues again after successfully completing therapy one year ago. You mentioned both anger and rebelling behavior and possible attachment disorder issues.
Regarding attachment disorder, if she is showing signs of this diagnosis, she would be dismissing your attempts at affection, acting out aggressively, failing to rely on you for basic needs, staying alone and removing herself from interaction. These are some of the symptoms that could occur.
Arguing and non compliance are the more difficult symptoms to pinpoint. Your daughter may just be reacting as a typical toddler. Many toddlers seek out ways to be more independent and sometimes test boundaries. This is particularly true if the child's personality is more bold and outgoing.
It would not hurt to have your daughter seen by a counselor for a thorough evaluation. If you feel comfortable going back to her former therapist, that would be fine, especially if she already has an attachment to her. This will aid in her recovery. If not, confer with her pediatrician for a referral, or if you have a children's hospital near you they often have child psychologists on staff.
There is also a couple of books I'd like to recommend for you. One is called "More than Love: Adopting and Surviving Attachment Disorder Children" by Sherril Stone. Also, the book "Building the Bonds of Attachment: Awakening Love in Deeply Troubled Children" by ***** ***** is helpful.
In the meanwhile, continue with reinforcing the boundaries and rules. Doing so in a safe and loving way will go a long way in helping control her behavior. Children need guidance and strong parenting, even if they fight against it. This is especially true with detachment disorder. These children need the consistency of healthy parental guidance to help them form secure, loving relationships.
Be sure to consider counseling for you and any other significant family member dealing with the behavior. The stress of being consistent and always there for your child can cause burnout and mild depression and/or anxiety. A good counselor can help you learn ways to care for yourself while you help your daughter.
I hope this has helped you,