Do you know the amount? Just enter it as Other self employment income or as Cash or General income. You don't need to get a 1099NEC or 1099K. Even if you did you can enter all your income as Cash. Only the total goes to schedule C.
How to enter income from Self Employment
https://ttlc.intuit.com/community/self-employed/help/how-do-i-report-income-from-self-employment/00/...
