I placed an order through PayPal on a website three weeks ago and the money came out of my bank account, however there is no record of this transaction anywhere on PayPal and I can’t file a dispute because no transaction is available. But I know I made the purchase because in my bank statement it says PayPal and the amount I spent.
If you bought something online with a debit or credit card and did NOT log into your Paypal account then of course it won't show on that Paypal account because you bought as a 'guest buyer'. However your seller may have processed that payment using their Paypal 'card reader' and so Paypal would show on your bank or card statement.
If you need to open a dispute for a 'guest buyer' transaction then you can.......
1. Phone Paypal customer services and see if they will open one for you (difficult at the moment due to covid) OR 2. Contact your card issuer for a chargeback.
Advice is voluntary. Kudos / Solution appreciated.