Who pays for gas connection fee?

[Jay Berts]

I have a unit where during COVID the gas was shut off to save money while it was not being rented out. 

We now have new tenants and after they got their first bill they saw a service activation  fee for $40 on the bill. They are requesting that I pay for the $40 fee on the bill. 

I was under the impression even if it’s a new connection the tenant is still responsible for the bill. 

The unit is in Chicago Illinois.