If notes are at all important for you, if you can read music, you should learn to write it. It really doesn't take long if you practice it a bit, and making a simple melody and chords (presumably, they don't want a full score!) leadsheet shouldn't be anything difficult.

It's like words... What's the point of reading, if you don't learn to write?!

I can both read and write music. Like the old joke, I try not to let it affect my playing.
If I have to, I will write out the lead line, but thought it would be far easier if someone had already done it! The ladies in the church can't read music, but they know when the notes go up on the staff to sing higher! So I guess they do sort of read music.
DonM

As little writing as I get to do these days, I always welcome a little transcribing task, especially if not too involved. Just like any muscle, the more you exercise it, the stronger it gets.

Back in the early 80's, before computers and notation software, I made a living up in NYC transcribing pop scores for albums, commercials and industrials. In ink! NYC had a thriving community of musicians that would write out the string, brass, bigband and orchestral parts for session work and live shows. Some very talented, and incredibly fast notation writers!

Now, sadly, all gone...

I still have my music calligraphy pens, but I don't think they've had ink in them since the 80's!

'Back in the day' - late 50's into '62, the accordion studio I studied/worked at had an accordion orchestra that played Classical music - 1812 Overture, Beethoven's 5th, Mussorgsky, Rossini, etc., etc., ... all the horn/woodwind parts had to be transposed from 'Eb/Bb' parts to 'C' for the accordion ... that was one of my jobs ...