From: Rabbi Moshe Sofer
To: Rabbi Avraham Schick
Individuals who purchased communal membership claimed mekach ta'us after the Chevra Kadisha imposed new burial fees, arguing they never would have bought membership knowing such fees would exist. The Chasam Sofer rules they have no monetary claim against the community, as umdena does not apply to defects arising in a purchased item after the sale, and the communal membership purchase falls outside all categories of umdena and implied warranty. However, he condemns the Chevra Kadisha's unilateral regulation as improper and urges them to retract it.
Source: Shu"t Chasam Sofer CM §70