Your return may have been selected for additional review, hence the delay. The IRS is also operating at a reduced capacity due to COVID-19, so this also contributes to the delay. When the IRS fully reopens, you can reach out to a representative at 800 829 1040 regarding the delay in your refund.
Regarding the stimulus, if you don't receive the stimulus payment in 2020, you can always receive it as a credit on your 2020 return in 2021. The stimulus is actually an ADVANCE on a credit on your 2020 return.
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