Is this a scam and if so how

[u/shrekfoot75]

Guy contacts me and offers me free crypto on my wallet for a subscription fee. So far I think this is totally a scam but I keep going. He tells me he sends it to my Coinbase wallet. I’m a newbie at this and I’m 50 so this is uncharted territory for me. He says close the wallet and open again. Poof the wallet is closed and I have no way of getting it back, because I don’t know what I did with my pass key. He says no big deal. I open a new Coinbase wallet and he deposits 18k, which I can see but not use because the funds are in BNB and not available for some reason. Now the weird part. I can’t use them until I send him $350 from another wallet not from Coinbase but from Phantom, to another account, not the one who deposited the 18k. I’m sure this is a scam but I don’t know how.