GST ON TWO WHEELER DEALINGS LIKE SUB AGENT

Accept booking from customer, take all documents from customer for registration & insurance. then buy vehicle from dealer and handed over it to customer. 

Invoices received on customers name and not on us. Basically we don't have purchases. We act like agent but not on paper.

turnover of actual sales ( turnover) more than 40 lacs, but commission income is not more than 20 lacs in a year. 

what are the provisions of gst applicability, penalty,etc

Thank you.