Fedex — overcharged for a courier

Address:

Jabalpur, Madhya Pradesh, 482001

Hi,
I shipped a courier from bombay to jabalpur on 6 june 2019.
The fedex pickup guy charged rs.3665.

I later called the customer care and they revealed that my courier was only billed for rs.2129.70 only.

A scam of rs.1535.3.
The fedex department has admitted the actual amount but are ignoring and not replying to the situation.

I am attesting all the documents, please review and help me get my money back.
And guide me so that i can lodge a formal complaint against this fraud.
Because i called and got my quote but how many others are being scammed without any knowledge.
The scammer name is dilip from mumbai, he operates in andheri area.