Customs has my package and i got a letter to get owndership of trademark?

okay so i recieved a letter from customs that i need to give them a letter for trademark ownership. is there any way i can claim it or anything i can do to get my package? since i contacted the seller and they have no letter whatsoever since its only replicas. Any things i can do? i need help i spent alot of money on this and now the seller is not trying to help me what soever. i even got insurance on the package and they said they cant do anything about it because customs still have it. what can i do with customs or the shipper?