How can I get the animal shelter to send the letter to the right people?

I picked up my in-laws dog at the animal shelter last month, (they were on vacation). I told them it wasn't my dog but they said they had to put my name down anyway. Now they are sending me letters to do the license and shot thing (I think my in-laws already did, but I can't get them to cooperate with me). Is there anyway I can get the animal shelter to take my name off and put my in-laws name on the mailing, I don't want to get a fine or have to go to court or anything. It isn't my dog so I don't have the dogs records to take to prove.