Print out the pages on card and laminate them (they last longer). Cut them out.
Pre-teach the expressions that are used when contracting a utility service.
Give a customer card to one student and a company card to the other.
The customer then phones the company and they have a timed role-play of two minutes.
Correct any mistakes after the role-play has been completed.
You could also mix up the cards for role-plays about wrong numbers.