What the lawyer is stating is correct provided it means that you want to hire him and hence you have to sign the vakalatnama
Vakalatnama is the urdu term which means the a person gives power to an advocate of his choice to plead and argue his case on his behalf. The procedure for filing vakalatnama is the person signed on it and the names of advocates appear on it.
if not than .
Missing one date would not matter much . As and when the next date is given which can be tracked on the court website you can attend the date along with your application for representing yourself as party in person and also submit your written statement .
Alternatively you can send in an application with your signature along with another person stating a genuine reason as to why you cant attend the and seek an adjournment from the court . Which i presume the court would grant the same .