It says “This order already has payment activity”

You clicked Payment on an order that already has a payment taken against it. The box shows what has been paid and asks what you want to do next.

If it says there’s a pending split payment

Part of this order was paid earlier and the rest is still open. The box shows how much has been paid and how much is left.

1. If you’re collecting the rest, click Continue existing split.
   It opens with the remaining balance already filled in.

If it shows a payment already taken on the order

Part of the order was paid by taking a payment towards it, not as a split. The box shows what has already been paid. Click Continue to take the rest.

This is what you see on a repair order with a warranty part — see Warranty on a repair order: both tabs show the whole balance.

Check what’s been taken

Go to Reporting → Transactions and search the invoice number. The amounts in the box and in the list include any additional fee, so they can be a little higher than the split screen shows.

If the split isn’t needed any more

Go to Open Orders → Split Transactions, click the three dots on the row, then Close Transaction, and give a reason. That only removes it from the list. Nothing is refunded or charged.

If the customer was charged twice

Refund the payment you don’t need. See Refund a payment or Refund part of a payment.

Related: Split a payment paid at different times · Split a payment across two methods · Find a payment