Buy 20x Keys for RL.. Seller Dont Have Keys....

I included a snapshot of what he said. I bought 20x Keys from a seller for Rocket League Steam. He contacted me and said “I dont have the keys, but I have items to sell. When i sell items Ill give you keys”. Shouldnt I be able to cancel the purchase under these circumstances? I dont know why someone would post an item for sale without even having the item. Makes no sense. If you could help me cancel this fast! Thatd be great, thanks!

If seller cannot deliver by the promised date (plus some extra time), you will have the option to cancel and get your money back.

If the seller is nice, he can tell you that he no longer have the keys and cancel it sooner.

lmfao but I shouldnt have to wait if he directly tells me he doesnt have
the item I purchased. The sale should be null and void at that very moment
and I should get a refund. Would make NO SENSE to have to wait 3 days, plus
24 hours… Legitly would be the worst customer service known to man if
thats how it would have went down. THANKFULLY he ended up selling w.e items
he was selling and got me the keys about 5 hours later. If I would have had
to wait 4 days for my money back Ida just cancelled my account right after
and went somewhere else. I included the snapshot of him saying he doesnt
have the item I bought. That right there should be enough to not have to
wait for him.