Under accrual accounting, you don’t need to receive payment to record the revenue. This is the reason for A/R. Revenue is recorded at the time of shipping. If the goods are rejected, then the value is recorded under Returns and Allowances and subtracted from gross revenue.
I’m sorry for throwing in the word “sales” when speaking about revenue. Perhaps this is why we seem to have difficulty finding common ground on such a simple subject. No disrespect intended.