Have you bought anything and paid for it via paypal since the payments went in??
The reason i ask is that if you have funds in your paypal balance and then buy something then paypal will sometimes take from those funds rather than from your normal funding source eg bank account or card.
To check go and click on the word "details" next to any recent paypal buying transaction and see if they were funded from your paypal balance ie buyers payments rather than your normal funding source.
Advice is voluntarily given. Kudos / Solution appreciated if I helped you.