In Missouri, your ESA housing rights rest first on state law. Section 213.040 of the Missouri Human Rights Act, Mo. Rev. Stat. § 213.040, makes it an unlawful housing practice to deny housing or impose different terms because of disability, which covers refusing a reasonable accommodation for an emotional support animal. This state protection is enforced by the Missouri Commission on Human Rights and remains fully active. The federal Fair Housing Act (42 U.S.C. § 3604) provides the same obligation, and that statute has not changed.
Landlords in Maryland Heights who refuse a valid ESA letter or continue charging pet fees may be in violation of the Missouri Human Rights Act and federal law. Complaints can be filed with the Missouri Commission on Human Rights.