Taking this statement : the client is being told that efforts were made to acquire their song unsuccessfully. While they don't know where or how, they are assured that reasonable efforts were indeed made.
Next, they are asked for their copy. Their response to that may offer further clues where it might be found with additional extraordinary efforts (such as "We heard it on YouTube" or WFUX/WSUX radio or.???").
By remastering it to a digital file, the notice is being made that I need this track in advance of the date, not at the event at the last minute. No CDs day of.
By returning it, they known it is merely a loan and that whatever time and expense they needed to outlay, they still reap the benefits.
By recommending to practice the dance to it, it is a really nice way of saying that the song choice may, at the moment be an emotional choice, having to dance to that selection, in the spotlight with every word in the song jumping out, the inability to dance to anything good let alone unusual, should be looked at and tested before the horror and embarrassment takes place. May times, that suggestion rightfully causes them to drop the track entirely.