Please help, $4800 Sent To Me By My Brother Has Been Hijacked By Nigeria Customs

My brother sent me a parcel from abroad using FedEx freight shipment in the parcel he stashed $4800 inside it when the parcel reached Nigeria at there headquarters in abuja I was asked to cover custom fee that has been N17,750 and home delivery N15,750 next I was mailed that after unboxing and reboxing for clearance money was found and it placed on ban and I can’t head to abuja to claim it because am in Lagos please what should I do. Who are the neccesary agency I could talk to.