Hold on to the disqualification notice so that in case it was a mistake you can show it for proof that you were excused from jury duty in case you get fined for not showing up.It could have been a error and meant for another person so just keep the notice for proof.

I had a friend who moved to Pennsylvania but Massachusetts didn't do their homework and he years later found he had a misdomeanor record and a $1000 fine against him.He had to show proof of a PA residence before the mailing date of the jury summons,yea mistakes happen!