An insurer may not engage in any retaliatory action against an insured, including canceling or refusing to renew a health insurance policy, because the insured or a person acting on the insured’s behalf has:

(1) filed a complaint against the insurer or against a preferred provider; or

(2) appealed a decision of the insurer.

See https://statutes.capitol.texas.gov/Docs/IN/htm/IN.1301.htm