In case post sale discount or discount sac or hsn code ???

HOW CAN BE THE HSN/SAC FOR DISCOUNT. AS IT IS NOT A SERVICE 

Suggest sac code for discount on sales

I think what ever the code you have used for service provided earlier for which you have given discount after post service.

Post sales discount is not part of taxable value and therefore not a part of GST. No SAC or HSN.

Just fill the HSN details of supplies you have made

Sir

But we have to reduce taxes also what we charged before in the invoice. We need to give our partners a regular back-end support discount, which was not on a single product but all turnover he made with us. that's why we need to make a separate Credit Note for the Invoice and hence need SAC code for it.