Deductions & credits

Deduct and expense are the same thing.  Yes if the 1099NEC doesn't include the referral fee you can't deduct it.  Or did you actual pay it out from your bank account?  

You either report 100% of your commissions before the fees then you can deduct the fees.

 

Or report the Net commissions you actual got after the fees.  Then  you can't deduct the fees again.