Did you issue a VAT invoice?
If yes, then you must issue a Credit note VAT inclusive, as the output VAT would have appeared on your VAT report for that period.
The credit note must be done for the current period, and depending on how you set up your system, it will either fall under Output VAT as a negative offset to the total output VAT, or it will fall under the Input VAT section, which will fall under the input/output VAT calculation.