In Black v. Victoria Lloyds Insurance Company, 797 S.W.2d 20, 33 Tex. Sup. Ct. J. 716 (Tex. 1990), the Supreme Court held that summary judgment was improper because a material issue of fact existed as to whether statements made on an insurance card varied with the written terms of a provision in the policy excluding coverage for permissive personal use of a vehicle. Id. at 26. Consequently, a fact issue existed as to whether the insurer had waived its right to enforce that particular provision as written in the policy. Id. at 26.