Don here from Shopify. :)
While we don't have access to or visibility of your PayPal account here it is likely that your payment has been routed to the default PayPal account created with the email address you used to sign up to Shopify.
If that is the case then you can simply get that dummy PayPal account added to your main account as an alias by their support team.
You can contact PayPal directly to confirm this and have them connect that account as an alias so you can claim your funds.
If there's anything else we can help with you can contact us via our
support site anytime. :)
All the best!