You’d better pay that payday loan back fast or it’s going to be a lot more than 400 dollars! I say this as someone who has come to blows with predatory lenders more than once. I’m so sorry you got scammed. It’s bullshit. Ebay is supposed to protect you from stuff like that. I wouldnt give up. It doesnt sound like they had grounds to suspend your account and even if they did, does that mean they’re no longer accountable for allowing a seller to send you an empty envelope? Did they pull that “we dont know that it was actually empty" crap? This pisses me off so much.
Pay back your loan. Dont let yourself be victimized again.