Transfer machine from one location to another query

Hi, we are working as a subcontractor and we have machines like hydra, cranes and different machines located at many states. 

Generally what we do whenever there is a shortage of machine we shift machines from one location  to another in different states. Now today we are transferring one part of big machine to another state but the transporter asked GST bill.

I tried to understand what actually he wants but he continously please provide GST bill with this. What we do now ?