The solution is to create CM in QB and then adjust the Vinosmith invoices when an account uses a credit on an invoice. For example, an invoice is paid only $220 instead of a $240 invoice, referencing a credit of $20. When you see the invoice's "partial payment" in VS (it would leave it open for $20), you mark it paid in full.
 

When this setting is enabled, QB Credit Memos, as applied to Invoices as Payments (in QB), will be reflected in Vinosmith as payments. Please Note: Credit Memo objects are not fully materialized, no customer balances are adjusted, etc. This option purely applies to credit memo payments as Vinosmith invoice payments. Please reach out to help@vinosmith.com to enable this setting.