Wanting to do a trade with middleman but one question

Okay, so im looking into buying a CS:GO knife with paypal cash, but im worried about one thing, when the seller gives the middleman the items and i send the money to the seller, and the seller lies and says no i didn't send the money will i be able to still get my knife by showing the recipt of payment and that it was his paypal i sent it to?
Will the middleman still give me the knife if i show him proof i paid and the seller keeps saying he didn't get the money?

Thanks,
M9s

If there is no way to receive my items after i did send the money to the email with proof then I will be better off buying one of the market

If the middleman is legitimate, they should check for proof before sending the items anywhere. So long as you have proof that you sent the money, you should get your items from the middleman.

I'd also expect that this seller would never get to work with a legitimate middleman again since they were trying to lie.

New post while I was typing... From what I understand, while buying from the Steam market is the safest way to get items for cash, it is a bit more expensive than some people will sell for paypal.

Thanks for the info, im getting a middleman from here and will be asking them the same question before i start the trade, and yes I know its better with paypal, but its the scams.