Usage notes:

• Credit memos must be created in ConnectWise PSA and batched over to QuickBooks Online using an Invoice Batch.
  • Credit Memos can only go from ConnectWise PSA  to QuickBooks Online, but not from QuickBooks Online to ConnectWise PSA .
• All payments and credit memos are to be applied to invoices in QuickBooks Online.
  • If the user applies any payments or credit memos in ConnectWise PSA , then they must apply the same payment/credit in QuickBooks Online before their next payment sync runs.
• Any Payment entered in QuickBooks Online that contains a credit memo can only be applied to one invoice per payment transaction.  If the user applies a Payment containing a credit memo to more than one invoice then the sync will fail.
  • The user can apply a credit memo to multiple invoices by splitting it across multiple payment records.
• A payment record without a credit memo on it can only be applied to a single invoice in a single transaction. If you receive a payment for multiple invoices, the payments must be applied to one invoice per transaction. If you apply a payment to multiple invoices in a single transaction, the payment sync will fail. 

Implementation details:

• Gozynta Mobius Payment Sync searches for payments in QuickBooks Online that have changed since last sync 
• When Gozynta Mobius finds a payment that has changed, it looks up the invoice and all related payments.
  • First Gozynta Mobius processes the credit memos.
    • All payments containing a credit memo must be linked to only one invoice, if there's multiple invoices on a Payment then we raise an error explaining the situation to the user, and link them to the Payment so they can fix it.
    • We remove all existing payments from the invoice before syncing payments from QuickBooks Online
    • If any credit memos are applied in ConnectWise PSA  that aren't applied in QuickBooks Online, then we will remove them.
      
    • If any credit memos are applied in ConnectWise PSA  for a different amount than in QuickBooks Online, then we fix the amount.
    • We add any missing credit memos.
  • We total all (non-credit memo) payments and apply to the invoice.
    • Since ConnectWise PSA  only supports 1 payment per invoice, Mobius sums all the payments and applies that total amount.
    • If a payment already exists then Gozynta Mobius will update it to the new amount.
    • The payment date in ConnectWise PSA  will be set to the date of the newest payment on this invoice in QuickBooks Online.

Note: Credit Memos don't apply directly to an Invoice in QuickBooks Online.  They apply to Payments which apply to Invoices.  Multiple Credits and Invoices can be on the same Payment, and it can be impossible to say that this specific Credit applies to this specific Invoice. For example:  You put a pile of money on the table from different sources, and then pay invoices with that money - it's meaningless to say that this particular invoice was paid with $xx from this particular source.  ConnectWise PSA  applies credit memos directly to invoices.  This is why we can only process a Payment record with a Credit Memo if it only contains one invoice.

Troubleshooting

• Encountered ConnectWise API Error: 400: payment object is invalid
• Payment Sync Error: Failed to update invoice with Credit Memo
• QuickBooks Online payment [link] has applied credit with multiple invoices. Only one invoice can be present per QuickBooks Online payment when applying credit.
• Payment Sync Warning: Credit Memo # not found in ConnectWise. This Credit Memo was used on QuickBooks Online payment(s) LINK

How to Create a Credit Memo in ConnectWise PSA