R.R.
I just want to point out that I work at a private school in Fort Worth, so obviously NOT the one you are having the dispute with. Look very closely at the contract you signed. Ours states specifically that transcripts will not be released if your accounts are not paid to date. It is the receiving school's decision whether to accept credits or not, not the sending school. We require a few different courses than the public school system, (in addition to the basic English, history, science, etc) so kids going into our upper school from the public schools often have to take additional classes to graduate, and some courses we offer are not offered in public school, so some of the credits are useless moving from private to public sometimes. Another point about your contract, it probably states that tuition is non-refundable, unless you've taken out tuition refund insurance.
Final point. The whole purpose of a private school is to NOT be ruled by TEA - why would you want to go to a private school governed by TEA? There are other accreditation agencies, such as NAIS, where the group of schools accredit each other through site visits, thorough review of standards and curriculum, etc. Believe me, it is very thorough, and very stringent. I would guess that your school is accredited through one of these agencies.
Those that are concerned it may be your school, keep in mind that people get disillusioned. Whether it's a doctor, a mechanic, a church etc. Especially where their children are concerned. Private schools still have kids, they still have bullying, drugs, favortism, cliques, etc. Some people get angry when their child fails a class, or gets disciplined. I'm not saying any of this is what happened, but don't jump and pull your child because one person is upset with that school.