Hi @Kaz24
Truth is that Intuit / QB do not understand CIS. Certainly not when it comes to credit notes.
By not building in the CIS function into Credit Notes, QBO treats them (for CIS purposes at least) as a part payment rather than a reduction in the value of the work done. Since CIS is cash-based (the deduction date is the date of payment) QBO is effectively saying that the work was done, the credit note was the payment & the deduction is owed to HMRC.
Ridiculous!
It's been raised as an issue on here many times over the last few years (both sales & purchase credits have the same problem).
The easiest option is persuade the customer to accept a corrected invoice. If you noticed it so quickly, they surely won't have logged it onto their system.
Alternatively, void & raise a new 'correct' invoice.
If the customer insists on a credit note, the only workaround I can find is discussed here ... https://quickbooks.intuit.com/learn-support/en-uk/transactions/how-do-i-create-a-cis-credit-note-to-...
Hope this helps.
