Hi Jon,
the #__matukio_bookings table is the log in your case. Every payment transaction is logged there (column payment_plugin-data)
Also concerning Paypal - if a user closes without completing the sale within Paypal the system marks them as booked
Every booking is pending until it gets paid (by default settings), maybe you set that every booking should be active setting to yes?
It's pending so that users can pay again later through their personal booking area. Pending places don't take seats etc.. If they cancel on paypal booking gets deleted, if they pay it gets activated and marked paid.
Kind regards,
Yves