Racket payment from mystified non-competitor you returned (10,5)
I believe the answer is:
protection money
'racket payment' is the definition.
'mystified non-competitor you returned' is the wordplay.
'mystified' indicates anagramming the letters.
'you' becomes 'ye'.
'returned' is a reversal indicator.
'ye' backwards is 'ey'.
'non'+'competitor'='noncompetitor'
'noncompetitor' with letters rearranged gives 'protectionmon'.
'protectionmon'+'ey'='PROTECTION MONEY'
'from' acts as a link.
(Another definition for protection money that I've seen is " What's extorted by gangsters".)