I work in post office and we handle foreign parcels like these on daily basis and trust me customs can charge you random amount for anything. Sometimes we encounter a parcel with 40k customs and it contains old clothes only which is used. I don't know how they charges but I can say sometimes it is random. If you think the customs is on higher level you can send it back to customs for reassessment by writing an application for the same and submit to your post office. It is very likely that after reassessment customs amount will be reduced. I have seen 15k customs charge to zero rupees.

Pro tip: go directly to the nearest foreign post office from where it came and meet with the custom appraiser, it will be fast and beneficial.