You can always sue in small claims unless you signed an agreement that required some other dispute resolution.
This answer is for informational purposes only and is not legal advice regarding your question and does not establish an attorney-client relationship.
It will be interesting to see the contract that you initially signed with the shop. There are some really strict requirements on auto repair shops under the Colorado Motor Vehicle Repair Act that can be used for suing them either in small claims court or in county court with an attorney if your damages exceed $7,500. You might want to contact a couple of attorneys in Pueblo that you might find here on Avvo.
The information provided in this answer does not create an attorney-client relationship. If you are interested in his legal services, feel free to call Chris at (303) 409-7635 at his law office in the Denver Tech Center. All initial consultations are free of charge.