Prices are managed in your POS and can not be modified in orderBilly.
Otherwise orderBilly could send orders to your POS with wrong prices and an error would occur.
This means, all pricing should be modified in your POS and then synced with orderBilly.
Go to your Lightspeed backoffice and look for the product of which you'd like to change the price.
Select the product and change its price.
Then go to the orderBilly backoffice and select 'catalogue' > 'products' and click on the 'sync with POS' button.
Done ✅