Can someone retrieve paypal money?

Had sold a ps4 on ebay classifieds exactly 1 month ago. The person paid the money via PayPal Buyer Protection… I sent it insured and also sent the tracking number to the buyer on eBay classifieds so that he can track the delivery. The goods arrived at the buyer everything was great. However, I forgot my password in my classifieds account and I don't keep the DHL tracking number anyway. And I noticed earlier that paypal is listed under the activities "Add tracking number"… If the buyer now activates buyer protection, can he simply take the money back? I also have no more evidence (no tracking number, no chat evidence) if this day should come. I heard that with paypal you have 3 months of buyer protection.

Reset password on eBay classifieds!

Why don't you just reset your password? With every, really every website there's the option "Forgot password" for exactly this case!

Otherwise there's not much left. PayPal only acts if you can show receipts, otherwise everyone could call and say something. Calling the Post / DHL customer service hotline doesn't help much either, because the first thing the questions will be "what is the tracking number"?

However, I forgot the password of my classifieds account

Reset password or contact eBay classifieds.

And I noticed earlier that paypal says "add tracking number" to the activities…

if the item is already with the buyer you no longer need to add this number.

If the buyer now activates buyer protection, can he simply take the money back?

no that just doesn't work and "take back" anyway. The buyer can activate buyer protection in the event of problems. It then becomes clear whether PayPal agrees with the buyer or not.

I heard that with paypal you have 3 months of buyer protection.

then you heard wrong. The buyer always has 6 months of buyer protection. (180 days)

If you do not abide by the rules and do not keep the necessary documents, then it can happen that you will lose out in the event of a buyer protection application.