Indian Oil Corporation [IOC] — Complaint against staff of Petrol pump who misbehaved along with his colleagues.

On 17.12.2020 I filled petrol worth Rs 300/- at Badachandra petrol pump, Keshari Nagar, Unit 5, Bhubaneswar, and gave Rs 500/- to the salesman named Dipuna and asked him to return me Rs 200/- due to me. Dipuna instead told me to park my bike and wait till he completes his account settlement process before he could return me the money.As I was getting let I asked him to return my money immediately. To this the sales person reacted with abuse and said I have to wait as long as he wants.Then I also reacted by pointing out his misbehaviour and went to lodge a complaint with the manager of the petrol pump. The manager very politely listened to me and the payment process was completed.But in the meantime The salesman(Dipuna) along with 10-12 other sales persons of the pump surrounded me and apart from abusing me in filthy language, tried to manhandle me. I was somehow rescued by the manager and other customers present. Even as I left the pump, the group of sales persons continued abusing me.
Why do I have to go through this harrowing experience ? What was my fault? I was only insisting that my time should not be wasted but the sales person rudely told me that I have to wait adding that he is hungry as it is his shift changing time and he can not return the money until he is finished with his accounting process. Is this the way the staff of a petrol pump treat a customer.
Please look into it and make the staff of the petrol pump understand the importance civilised behaviour which every customer expects.