Income from 2019 returned in 2020

[elpadre]

I received income (that I paid taxes on) in 2019 that I had to pay back in 2020 - when the events were canceled.  How do I handle this on 2020 return?

[PhylI]

What Account did you debit when you wrote the check (cash credit)? 

If you have a Sales (Services) Returns and Allowances account, that should have taken the Debit.  Your current year's Sales/Services will be reduced by those amounts and taxable sales for this year will be lower. Should equal out.