MX Merchant Ideas

We use a third party POS system to run our transactions.  We provide the invoice number but it is not showing in Mx Merchant.  I have had 2 days this month where the amount that paytrace says we took in one amount but MxMerchant is showing a different amount.  I have no way of knowing what order did not deposit in MxMerchant because we run a lot of the same amounts.  I need our po# in the invoice column.