My husband and I only received 1/2 of our stimulus checks! We should have received $4200 (me, him, dependent) but only got $2100. Why? We don't make the max amount.

We only got 1/2 of our stimulus check, we are well under the threshold, we've already completed our 2020 taxes, added our baby who was born in 2020, have no outstanding debt, and the calculator says we should get $4200.