What to do if the emloyer can't be served?

This case is taking place in TN. There is NO child support involved, just personal loans. The debtor works at a nightclub that doesn't open until late, and the sheriff has told me they have been to the club at least 15 times in 3 weeks trying to serve the garnishment papers to the debtor's employer (the club's owner). They are not having any luck in doing so, and are unable to tell me what steps to take if they wind up having to sent the forms back to the courthouse. Can anyone advise me what to do if the garnishment forms cannot be successfully served on the debtor's employer? The case has already been through civil court, and the debtor refuses to go along with the judges' orders and pay what he owes me, that is why I am trying to garnish his wages now. What are my other options if we cannot get the garnishment papers served? Thank you!