You can actually dispute this kind of transaction because you use mode of payment as goods. Just don't tell to the support that you use it to buy bitcoin because it will fall to digital goods which is no dispute. Just tell that you bought some goods and it didn't arrive to yoo. No need for screen shot to present.
Just for clarification, paypal DOES cover digital goods i read about it somewhere on their policy changes afew months ago. However I do not know how they will handle bitcoin transactions. Forums all over consider paypal an outcast and I would think for good reason, its enough for me to avoid paypal like the plague for selling btc.
Declaring as goods was definitely a big mistake cos the onus is on you to show delivery and that counts as courier proof not blockchain screenshots. I think declaring as services now is safer then declaring as goods as you no longer need to show as much detailed proof as you did for goods. Goods can also be refunded when a user declares did not get it in the correct state which for services declared as goods is a default chargeback.