Customer brings cash deposits totaling $21,788.00. The cash is deposited into 6 different accounts (2 corporate and 4 personal accounts).
The deposits would be for 2a, 2b and 2c so we would mark 2a as per the instructions.
$6,980 is for the benefit of the person who brings in the
deposits.
What figure do we list on item # 21? Would we list the total $ 21,788.00 the customer brought in or do we list only the
amount he actually benifited from which would be $$6,980?

You list the amount that involves the customer whether they benefitted from the deposit or brought them in. Since all of the transactions involved this individual one way or the other, you would list $21,788 for the customer.