A judge has ordered the city of Des Moines to stop communicating with individuals and businesses about a lawsuit in which the city was found to have collected illegal utility fees.

The city must return about $40 million to gas and electric customers of MidAmerican Energy Co. after a Des Moines woman successfully sued claiming a portion of the franchise fees the city collected between 2004 and 2009 were illegal.

Attorneys are working out how the city will refund the money to about 100,000 customers.

At a recent hearing Judge Joel Novak learned some business, organizations, and individuals were asked by a city council member to sign form letters indicating they would voluntarily forego their share of the money.

On Thursday Novak ordered the city to stop soliciting.