The mothers are dissatisfied with the way in which Contreras accounts for donations made on behalf of Mariachi Cascabel.
Contreras said the women's attempts to sully her reputation are unfounded and vindictive.
She said she has proof all donations made to the group have been accounted for and said the non-profit group's books are an open record.
"It's the same thing as before. I can prove everything. I'm not worried about it," Contreras said.
She said the European festival and trip to Rome was, "like a dream. It was really nice — when the parents weren't too busy messing everything up."
Parent Virginia Sanchez said, "Mariachi Cascabel is the consistency of the parents and the hard work of the kids."
According to the Internal Revenue Service, Mariachi Cascabel is a non-profit group founded by Contreras and Raymundo Ojeda. The group's financial records with the IRS are under Ojeda's name, according to Contreras.
She has heard of the mothers plans to form a new group but isn't concerned.
She said she will add new kids to Mariachi Cascabel if the parents take their children out of the group and is planning an Imperial Valley music festival.
She needs to put on a festival and invite and house the Austrian group that invited her group to the European festival.
While the mothers plan to disassociate with Contreras they do acknowledge that their children would not have been able to go to Europe this year if not for Contreras and Ojeda.
Was the trouble and the fighting and the personality conflicts worth it all for the sake of their children?
The mothers nodded affirmatively, but quickly added the trip could have been better.
Contreras agrees with the mothers on that point.
"It was very sad. All the very negative things were on the bus or at 2 or 3 o'clock in the morning, but I didn't let it get to me.
"I was not involved physically. I was not involved. I didn't confront them. To me everything was fun," she said.
Contreras also thinks all of the bickering and squabbles were worth the trouble.
She said she knelt next to the pope and prayed, "Thank you God for choosing me to bring all of these people to you."
"He chose me to take them and bring them back. I gave them what I promised to give them," she said.
"It was beautiful," she added.