Customs fine & penalty

I'm currently stuck in a weird situation. Mumbai customs have detained my article because the shipper mis-declared the value. Actually, the article is a gift from my employer - and they use 3rd party services to consolidate and ship the items to remote employees based in several countries. I wasn't aware of this mess until I got to know about it from FedEx. The customs asked for an explanation from me to why was it misdeclared. In fact, they found the original invoice in the packaging too. It's just that the shipper mis-declared the value to FedEx. I got an explanation from the shipper too stating that it was an error from their end - and stated to refer to the original invoice for actual valuation. Today, I got a mail from FedEx stating that customs want a letter from consignee (me) to request to customs to not to issue personal hearing / show cause notice - and accept to pay fine / penalty. They have also levied 77% duty. And I have to pay additional fine / penalty. The goods are just roller stakes on which the duty is very low. How could they ask for 77% duty - and why should I pay the fine / penalty when it's not even my fault? What's the solution on this? Why could I tackle this issue legally ? What's a show cause notice? Will they register a case?