Defamation of character

My husband was summones at work on friday 18th of August, by sheriff. With a letter stating that he owes this clinic cape animals medical centre R 6000 for using their service in 2015 apparently. Which is falsely stated, he never owned any animals, secondly the Identity numbers on the letter is not his either, but his work address appears.which set him in bad light at work for the position he helds at work and such huge embarrassment for him due through it all I find it disrespectful no apology was given and when I called all they said there's nothing they can do because its already handed to the sheriff.